Events: Centre: Physics Centrehttp://www.chalmers.se/sv/om-chalmers/kalendariumUpcoming events at Chalmers University of TechnologyWed, 24 Apr 2019 17:27:24 +0200http://www.chalmers.se/sv/om-chalmers/kalendariumhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Masterpresentation_Andreas-Tatidis_190424.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Masterpresentation_Andreas-Tatidis_190424.aspxMaster's thesis presentation: Andreas Tatidis, MSc<p>FL51</p><p>​ Title: Modelling of the Effect of Stationary Fluctuations in Nuclear Reactors Using Probabilistic Methods</p><h4 class="chalmersElement-H4">​<span>Abstract:</span></h4> <div>A Monte-Carlo-based method for determining the effect on the neutron flux of stationary fluctuations in 1D  and 2D is proposed in this study. The cross-sections of the two-group balance equations relying on the diffusion approximation in the frequency domain are split into their real and imaginary parts, and a modified Green's function technique is used. In this technique, the balance equations for the real part of the balance equations are mimicked with Monte Carlo using an equivalent subcritical system. The exact same balance equations are obtained for the imaginary part. The coupling between the real and imaginary parts are resolved outside of the Monte Carlo Code, taking advantage of the properties of the Green's function. The amplitude and phase close to the point of perturbation agree well with diffusion based-codes such as CORE SIM. This method is applicable to any frequency, and any type of cross-section perturbation. The Green's function is furthermore found to be insensitive to frequencies around and above the plateau region. Using the Green’s function at one given frequency within this frequency range has thus a negligible impact.</div> ​​https://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Roland_Jago_190425.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Roland_Jago_190425.aspxRoland Jago, Physics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​ T​itle of doctoral thesis: &quot;Spatiotemporal carrier dynamics in graphene</p><h4 class="chalmersElement-H4">​Abstract:</h4> <div><span style="background-color:initial">Graphene as an atomically thin material exhibits remarkable optical and electronic properties that suggests its technological application in novel optoelectronic devices, such as graphene-based lasers and photodetectors. We show that it is possible to achieve a stable population inversion in graphene, which is crucial for using graphene as an active material in a nanolaser.</span></div> <div> </div> <div>Depending on the experimental conditions there are different mechanisms determining the optical response and the resulting photocurrent. In this thesis we provide microscopic insights into the photoconduction and the bolometric effect as important mechanisms in a graphene based photodetector. With our research we are able to identify microscopic knobs to tune the photocurrent.</div> <div> </div> <div>Furthermore, we study the interplay of the carrier relaxation and transport phenomena. We reveal that in the presence of an external electric field an efficient dark carrier multiplication occur, which increses the carrier density, and even enhance the field-induced current. Moreover, we provide a microscopic description of the spatiotemporal dynamics of optically excited carriers, which create density and temperature gradients resulting in a diffusion of carriers.</div>https://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Laura_Mazzei_190426.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Laura_Mazzei_190426.aspxLaura Mazzei, Physics<p>KA Lecture hall, Chemistry and Chemical Engineering, department, Kemigården 4, Kemi</p><p>​Title of doctoral thesis: &quot;Local structure and dynamics of proton- and hybride-ion conducting perovskite type oxides&quot;.</p><h4 class="chalmersElement-H4">Abstract:</h4> <div><span style="background-color:initial">T</span><span style="background-color:initial">he production of sustainable and clean energy is one of the most important challenges of our time, and it has motivated a great amount of research work in very different areas. Hydrogen fuel cells are amongst the most promising environmental-friendly devices, but their full exploit requires to develop novel components that satisfy the requirement for practical, every day, application. Of crucial importance is to find conducting materials (electrolytes) which can work between 200 and 500 °C and which show high conductivity. Among others, proton conducting oxides with so-called perovskite structure have emerged as some of the best candidates as electrolyte materials in this temperature range. Yet, in order to design materials tailored for application, one needs first to gain a better understanding of how protons move and how the properties of the material influence the way protons move.</span></div> <div><br /></div> <div> </div> <div>In this thesis, I investigated one of the most well-known groups of proton conducting perovskite oxides, BaZrO3 based materials, and another, novel, family of energy-relevant perovskite oxides, oxyhydrates BaTiO3-xHx. For the investigations I mainly used light- and neutrons-based techniques. The basic idea of these techniques is to send a beam, of light or neutrons, on a material, and to study how the beam is modified due to the interaction with it. In this way it is possible to obtain very important information about the position of the atoms (structure) and the way they move (dynamics) in the material. </div> <div> </div> <div><br /></div> <div> </div> <div>I specifically looked at the relationship between local structure, i.e. the structure on nanometer scale, and the way hydrogen moves. This helped us to better understand the fundamental properties of proton conducting oxides, especially on the local scale, and how these are affected by the chemical composition of the materials. More generally, the novel insights provided by this work contribute to the understanding and further development of materials for energy application.</div>https://www.chalmers.se/en/departments/mc2/calendar/Pages/Janine-Splettstoesser.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/Janine-Splettstoesser.aspxInauguration lecture - Janine Splettstößer<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Title: Heat engines and thermoelectric devices at the nanoscale</p><img src="/SiteCollectionImages/Institutioner/MC2/Staff/Janine-170_220.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px" /><strong>Abstract:</strong> ​In this talk, I will give an introduction on nano-scale systems, such as quantum dots, as possible implementation of heat-engines and refrigerators. <br />Compared to classical analogues, nanoscale thermodynamic machines exhibit a number of crucial differences. These differences stem from the smallness of nanoscale devices leading to quantization effects, but also inhibiting an equilibration of device elements during their operation. In this talk, I will in particular focus on novel phenomena expected in nanoscale heat engines, when brought out of equilibrium. <br /><br /><br />https://www.chalmers.se/en/departments/mc2/calendar/Pages/GCCS-Christoph-Stampfer.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/GCCS-Christoph-Stampfer.aspxBoosting the carrier mobility of graphene<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Graphene Centre Seminar with Christoph Stampfer​ JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, Germany The Graphene Center at Chalmers (GCC) will organize a monthly GCC seminar on the recent advances in the field of graphene and 2D materials. The seminars will be on a monthly basis and will take place every last Monday in the month. ​ Welcome to attend!</p><h5 class="chalmersElement-H5">​Abstra​ct:</h5> <div>The carrier mobility is an important figure of merit for electrical conductors, characterizing how quickly a charge can move in response to an electric field. High carrier mobilities play a fundamental role for high frequency electronics, integrated optoelectronics as well as for sensor and spintronic applications, where device performance is directly linked to the magnitude of the carrier mobility. Thanks to the suppression of backscattering guaranteed by pseudo-spin conservation and weak electron-phonon interaction, graphene outperforms all known materials in terms of room temperature mobility. </div> <div>I will show that the best performance of state-of-the-art graphene devices -- which is close to the theoretical limit set by electron-phonon scattering -- can be surpassed by more than a factor four employing van-der-Waals heterostructures consisting of tungsten diselenide (WSe2), graphene and hexagonal boron nitride. This enhancement, which leads to extraordinary high room temperature mobilities of up to 350,000 cm2/(Vs), can be understood in terms of a suppression of  electron scattering with acoustic phonons. This is most likely due to the mechanical coupling between graphene and tungsten diselenide, which converts graphene's acoustic phonon branches into finite-energy interlayer shear modes.​</div> <div><br /></div> <div>Figure: <span style="background-color:initial">Illustration of a quasi-two dimensional heterostructure consisting of </span><span style="background-color:initial">2 layers of hexagonal boron nitride (bottom), graphene and 2 layers of WSe2</span><span style="background-color:initial">​​</span></div>https://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-B-Karpiak.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-B-Karpiak.aspxLinnaeus Coffee Seminar with Bogdan Karpiak<p></p><p>​Title: TBASpeaker: Bogdan Karpiak from Quantum Device Physics laboratory​ at the Department of Microtechnology and Nanoscience, Chalmers</p>​<span style="background-color:initial">Coffee and cake will be served before the talk at 14.00</span><div><div>Welcome!</div> <div><br /></div> <div></div></div>https://www.chalmers.se/en/centres/gpc/calendar/Pages/COLL_Federico_Capasso_190502.aspxhttps://www.chalmers.se/en/centres/gpc/calendar/Pages/COLL_Federico_Capasso_190502.aspxBeyond Refractive and Fresnel Optics: Metasurface “Flat” Optics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Speaker: Federico Capasso, Harvard University, USA</p><h4 class="chalmersElement-H4">​Abstract:</h4> <div>The design of fundamental optical components such as lenses, gratings, and holograms has remained essentially unchanged for decades, relying on textbook refractive and diffractive optics. Subwavelength structured surfaces known as metasurfaces are leading to a fundamental reassessment of such designs with the emergence of optical components that circumvent the limitations of standard ones. This led us to demonstrate ultrathin dielectric metalenses that correct monochromatic and chromatic aberrations across the visible without using complex composite lenses, high resolution ultracompact miniature spectrometers, novel endoscopes for bronchial cancer detection and metasurfaces that create complex structured light via entanglement of spin and orbital angular momentum degrees of freedom. I will conclude by presenting a new approach to polarization control that doesn’t use standard polarization optics, with superior performance in terms functionality and miniaturization compared to conventional polarimetry and polarization imaging.​</div>https://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Alvaro_Posada-Borbon_190503.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Alvaro_Posada-Borbon_190503.aspxAlvaro Posada-Borbon, Materials Science<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​ Title of thesis: &quot;CO2 activation for methanol synthesis on copper and indium oxide surfaces&quot;.</p><h4 class="chalmersElement-H4">Abstract:</h4> <div><span style="background-color:initial">Catalytic recycling of CO<sub>2</sub></span><span style="background-color:initial"> to added-value chemicals, such as methanol (CH<sub>3</sub></span><span style="background-color:initial">OH), has been proposed as a possible way for sustainable production of fuel and chemicals, in addition to providing a route to mitigate climate change. Multiple systems are known to be active for the conversion of CO<sub>2</sub></span><span style="background-color:initial"> to methanol, and the state of the art catalyst is Cu/ZnO/Al<sub>2</sub></span><span style="background-color:initial">O<sub>3</sub></span><span style="background-color:initial">. This catalyst is, however, known to deactivate rapidly. Moreover, there is no scientific consensus on either the active phase or the reaction mechanism. In response to this, the search for a longer-lasting catalysts for methanol-synthesis has been intense. In recent years, an In<sub>2</sub></span><span style="background-color:initial">O<sub>3</sub></span><span style="background-color:initial">/ZrO<sub>2</sub></span><span style="background-color:initial"> catalyst has attracted much attention, thanks to its high selectivity, activity and durability.</span></div> <div><br /></div> <div> </div> <div>In this thesis, we investigate the surface active phase and its effect on CO<sub>2</sub> adsorption on Cu(100) and In<sub>2</sub>O<sub>3</sub>(110) with the use of density functional theory (DFT) calculations and <em>ab-initio</em> thermodynamics. Our results are compared to ambient pressure X-ray photoelectron emission spectroscopy (XPS) experiments. CO<sub>2</sub> adsorption is the initial step in the reduction process. Hence, understanding of the active catalyst phase, and its effect on the adsorption process, is the first step for the rationalization of the catalytic processes on these systems. Simultaneously, understanding the electronic structure that allows for the high activity, might aid the rational design of better catalysts for CO<sub>2</sub> activation.<br /><br /></div> <div> </div> <div>Our results show that Cu(100) oxidizes from the pristine surface to a p(2×2) overlayer <span style="background-color:initial">at 0.25 ML followed by a reconstruction to a (2</span><span style="color:black;font-family:cambria, serif;font-size:10pt;background-color:initial">√</span><span style="background-color:initial">2 × </span><span style="background-color:initial;color:black;font-family:cambria, serif;font-size:10pt">√</span><span style="background-color:initial">2</span><span style="background-color:initial">)R45<sup>o</sup></span><span style="background-color:initial"> (MR) structure at 0.50 ML. Moreover, dissociative adsorption of CO<sub>2</sub></span><span style="background-color:initial;font-size:10.5px;line-height:0;vertical-align:baseline;bottom:-0.25em"> </span><span style="background-color:initial">on Cu(100) occurs predominantly at surface steps. In<sub>2</sub></span><span style="background-color:initial">O<sub>3</sub></span><span style="background-color:initial">(110) is found to heavily hydroxylate in presence of H<sub>2</sub></span><span style="background-color:initial"> and/or H<sub>2</sub></span><span style="background-color:initial">O. Hydroxylation with H</span><span style="background-color:initial;font-size:10.5px;line-height:0;vertical-align:baseline;bottom:-0.25em">2</span><span style="background-color:initial"> causes the undercoordinated In-sites to change oxidation state </span><span style="background-color:initial">(</span><span style="background-color:initial">from In<sub>3</sub></span><span style="background-color:initial">+ to In<sub>2</sub></span><span style="background-color:initial">+), while H<sub>2</sub></span><span style="background-color:initial">O does not. We suggest that the redox capacity of the undercoordinated In-site are responsible for the adsorption of CO<sub>2</sub></span><span style="background-color:initial"> on indium oxide, </span><span style="background-color:initial"></span><span style="background-color:initial">whereas oxygen vacancies act as spectators. Our results are in qualitative agreement with the experimental observation of heavy hydroxylation and the suppression of the reverse water gas shift on indium oxide.</span></div> <div><br /></div> <div> </div> <div><em>Keywords: Heterogeneous catalysis, Density functional theory, Methanol conversion,</em></div> <div> <em></em></div> <div><em>CO<sub>2 </sub></em><em>reduction, Copper surface, Indium oxide​​</em></div> ​​https://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-X-Gu.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-X-Gu.aspxLinnaeus Coffee Seminar with Xiu Gu<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​Title: TBASpeaker: Xiu Gu from Applied Quantum Physics laboratory at the Department of Microtechnology and Nanoscience, Chalmers</p>​<span style="background-color:initial">Coffee and cake will be served before the talk at 14.00</span><div><div>Welcome!</div> <div></div></div>https://www.chalmers.se/en/departments/physics/calendar/Pages/Seminar_Alejandro_Franco_190508.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Seminar_Alejandro_Franco_190508.aspxARTISTIC Project: Multiscale modeling of Lithium Ion Battery manufacturing<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​Seminar by Professor Alejandro A. Franco​, Université de Picardie Jules Verne, Amiens, France Junior Member of the Institut Universitaire de France (IUF) Leader of the Theory Open Platform at the ALISTORE European Research Institute ERC Consolidator Grantee (PI of the “ARTISTIC” project.)</p><h2 class="chalmersElement-H2">​Abstract: </h2> <div>After decades of research and more than twenty years of market development, Lithium Ion Batteries (LIBs) have contributed to the commercial success of portable electronics and constitute nowadays the most used battery type in modern Electric Vehicles (EV). However, regarding EV applications, LIBs have reached a point where optimization of their electrode mesostructure is vital to decrease their cost and to achieve even higher gravimetric and volumetric energy densities. The porous electrode mesostructure and its associated properties (e.g.  porosity, tortuosities, electronic conductivity) strongly depend on the adopted fabrication process and parameters, such as the slurry composition, the solvent evaporation rate and the calendering pressure. Enabling precise control of material arrangement and distribution in the electrodes is of paramount importance for designing the next generation of rechargeable battery electrodes. As a consequence, there is a crucial need of a general theory serving as a guide to electrode fabrication for the optimization of their mesostructure. </div> <div> </div> <div><br /></div> <div> </div> <div>In this seminar, I will discuss our efforts at developing a multiscale computational platform aiming at predicting the link between fabrication parameters and electrochemical performance of lithium ion battery cells. The practical implications of such a platform towards the fabrication process optimization and the integration of new battery chemistries are discussed.</div> <div> </div> <div><br /></div> <div> </div> <div>Finally, the interest of using Virtual Reality (VR) to explore in an immersive and interactive way data and electrode mesostructures arising from the simulations will be briefly discussed, on the basis of both research and teaching activities being carried out by us at Université de Picardie Jules Verne. A VR experience will be also proposed to the audience who will have the opportunity to fly inside porous electrodes!   </div> ​https://www.chalmers.se/en/departments/mc2/calendar/Pages/LC-Jean-Marc-Triscone.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/LC-Jean-Marc-Triscone.aspxInterfacial Effects and Superconductivity in Oxide Heterostructures<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​​Linnaeus Colloquium with Jean-Marc Triscone, DQMP, University of Geneva, Switzerland</p><div><h5 class="chalmersElement-H5"><span>​​Abstract:</span></h5></div> <p class="chalmersElement-P"> <span></span></p> <p class="chalmersElement-P"><span lang="EN-US">Oxide materials display within the same family of compounds a variety of exciting electronic properties ranging from ferroelectricity to ferromagnetism and superconductivity. These systems are often characterized by strong electronic correlations, complex phase diagrams and competing ground states. This competition makes these materials very sensitive to external parameters such as pressure or magnetic field. An interface, which naturally breaks inversion symmetry, is a major perturbation and one may thus expect that electronic systems with unusual properties can be generated at oxide interfaces [1,2]. A striking example is the interface between LaAlO3 and SrTiO3, two good band insulators, which was found to be conducting [3], and, in some doping range, superconducting with a maximum critical temperature of about 300 mK [4]. </span></p> <p class="chalmersElement-P"> </p> <p class="chalmersElement-P"><span style="background-color:initial">In this presentation, I will motivate the search for novel properties at oxide interfaces before to focus on the LaAlO3/SrTiO3 interface. In this system, the thickness of the conducting layer is found to be a few nanometers at low temperatures. This electron liquid with low electronic density, typically 5 1013 electrons/cm2, and naturally sandwiched between two insulators is ideal for performing electric field effect experiments allowing the carrier density to be tuned and superconductivity to be switched on and off. I will discuss the origin of the electron liquid [5]; superconductivity [4,6]; field effect experiments and the phase diagram of the system [6]; and the comparison between superconductivity at the interface and in bulk doped SrTiO3 before to give perspectives on the future of this research field [7].</span><span style="background-color:initial"> </span></p> <p class="chalmersElement-P"> </p> <p class="chalmersElement-P"><span lang="EN-US">[1] J. Mannhart and D. Schlom, Science 327, 1607 (2010).<br /></span><span lang="EN-US" style="background-color:initial">[2] </span><span lang="EN-US" style="background-color:initial">P. Zubko, S. Gariglio, M. Gabay, P. Ghosez, and J.-M. Triscone, Annual Review : Condensed Matter Physics 2, 141 (2011).<br /></span><span style="background-color:initial">[3] A. Ohtomo, H. Y. Hwang, Nature 427, 423 (2004).<br /></span><span style="background-color:initial">[4] N. Reyren, S. Thiel, A. D. Caviglia, L. Fitting Kourkoutis, G. Hammerl, C. Richter, C. W. Schneider, T. Kopp, A.-S. Ruetschi, D. Jaccard, M. Gabay, D. A. Muller, J.-M. Triscone and J. Mannhart, Science 317, 1196 (2007).<br /></span><span lang="EN-US" style="background-color:initial">[5]</span><span lang="EN-US" style="background-color:initial"> M.L. Reinle-Schmitt, C. Cancellieri, D. Li, D. Fontaine, S. Gariglio, M. Medarde, E. Pomjakushina, C.W. Schneider, Ph. Ghosez, J.-M. Triscone, and P.R. Willmott, Nature Communications, 3, 932 (2012).<br /></span><span style="background-color:initial">[6] A. Caviglia, S. Gariglio, N. Reyren, D. Jaccard, T. Schneider, M. Gabay, S. Thiel, G. Hammerl, J. Mannhart, and J.-M. Triscone, Nature 456, 624 (2008).<br /></span><span style="background-color:initial">[7] S. Gariglio, M. Gabay, and J.-M. Triscone, Research Update, APL Materials 4, 060701 (2016).</span></p> <p class="chalmersElement-P"> </p>https://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Olov_Windelius_190510.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Olov_Windelius_190510.aspxOlle Windelius, Physics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​ Title of thesis: &quot;A Collinear Angle-Resolved Photoelectron Spectrometer: Instrumental Design and Photodetachment Measurements</p><h4 class="chalmersElement-H4">Abstract:</h4> <div><span style="background-color:initial">For more than half a century, photoelectron spectroscopy has been used to investigate atoms, ions and molecules. Various techniques have been developed in order to measure electron energies and angular distributions using different radiation sources such as lasers and synchrotrons. In this work, a new spectrometer design for measurements of angular distributions of photoelectrons using synchrotron radiation is presented. The design takes advantage of a collinear interaction region, which is two orders of magnitude larger than obtainable with the crossed beams method. The number of events per time unit is thereby substantially increased compared to regular angle-resolved photoelectron spectrometers. This is of great value when the radiation source has a low photon flux and the background is large due to the high photon energy. The spectrometer has been tested on systems where the angular distribution is well-known, in order to develop methods for compensation of the angular transformation between the ion rest frame and the lab frame. Further, a measurement of the angular distribution of a negative ion, P−, over a wide range of photon energies has been conducted. The results are in agreement with previous measurements and, more importantly, reveal new and valuable information about the theoretical modelling of angular distributions.</span></div> <div> </div> <div>The experiments presented show that the spectrometer can be used to measure angular distributions of atomic and molecular ions, and that it can be a valuable asset at synchrotron beamline endstations. This work also includes a photoionization cross section measurement of Zn+, performed using the synchrotron at the Advanced Light Source (ALS), Berkeley, CA.</div> <div> </div> <div><br /></div> <div> <em>Keywords: Angular distributions, photoelectron spectrometer, photodetachment, photoionization, synchrotron radiation.</em></div>https://www.chalmers.se/en/departments/mc2/calendar/Pages/William-Hallberg---Microtechnolgy-and-Nanoscience---MC2.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/William-Hallberg---Microtechnolgy-and-Nanoscience---MC2.aspxWilliam Hallberg, Microtechnolgy and Nanoscience - MC2<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​ Title: Analytical Approaches to Load Modulation Power Amplifier Design</p> <p>William is a PhD student at the Microwave Electronics Laboratory</p> <p>Faculty opponent is: Dr. Frederick H. Raab, Green Mountain Radio Research LLC, U.S.A.<br />Examiner: Prof. Herbert Zirath<br />Main supervisor: Prof. Christian Fager</p>https://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Iwan_Darmadi_190513.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Iwan_Darmadi_190513.aspxIwan Darmadi, Material Science<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​ ​Title of thesis: &quot;Palladium-based Nanoplasmonics for Ultrafast and Deactivation-Resistant Hydrogen Detection</p><h4 class="chalmersElement-H4">Abstract:</h4> <div><span style="background-color:initial">Hydrogen gas is the main energy carrier in the hydrogen economy scenario. hydrogen is attractive as energy carrier since the energy produced by reaction with oxygen only produces water as by-product. Hydrogen, however, is flammable in ambient air even at low concentration i.e. 4 vol.%. Therefore, safety system is mandatory to monitor any leaks. The hydrogen sensor technology today, unfortunately, has not been able to pass the stringent safety standard.</span></div> <div> </div> <div>Motivated by the safety issue, we exploit the localized surface plasmon resonance (LSPR) of palladium (Pd) nanoparticles to build optical based hydrogen sensors. Unique features of an optical sensor with respect to other types are the inherent free-of-spark operation, the possibility to perform a remote readout and the possibility of multiplexing. Pd, however, has limitations which hinders the hydrogen sensor to meet the requirement.</div> <div> </div> <div>In this thesis I report two aspects: development of the Pd-based nanoplasmonic sensor and fundamental studies on the hydrogen-Pd nanoparticle. The implementation aspect includes two different strategies to optimize the sensor: (i) Au and Cu alloying and (ii) polymer (PMMA, PTFE) coating. The fundamental aspect covers two studies on: (i) the correlation between the absorbed hydrogen and the optical response and (ii) the (de)hydrogenation of surfactant/stabilizer-coated nanoparticle.</div> <div> </div> <div>We managed to achieve excellent hydrogen sensor performance that meets the strict demand and we acquired deeper insight on the hydrogen sensing mechanism which is important for the sensor design. The findings hopefully contribute to the safety aspect of hydrogen economy and enable wider applications. </div> <div> </div> <div><br /><em>Keywords: localized surface plasmon resonance, nanoparticle, plasmonic sensing, hydrogen, palladium, Pd, palladium hydride, palladium alloy, polymer, surfactant, hydrogen sensor.</em></div>https://www.chalmers.se/en/departments/physics/calendar/Pages/Inauguration_electronmicroscope_190515.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Inauguration_electronmicroscope_190515.aspxInauguration of Unique Advanced Transmission Electron Microscope<p>Gustaf Dalén-salen, lecture hall, Chalmers Tvärgata 5, Gustaf Dalénsalen</p><p>​ A dedicated day with internationally leading scientists including a special lecture by the Vice President of the Max-Planck-Society, Professor Ferdi Schüth. Registration needed for lunch, more information will follow shortly.​</p><h4 class="chalmersElement-H4">​Programme:</h4> <div><span style="background-color:initial">09:30 – 10:00</span><span style="background-color:initial;white-space:pre"> </span><span style="background-color:initial">Registration, Coffee/Tea</span></div> <div> </div> <div>10:00 – 10:45<span style="white-space:pre"> </span>Seminar, Professor Ferdi Schüth, Vice President of Max-Planck-Society<br /><em>“Materials for Energy Technology- Importance of Material Structure and Advanced Electron Microscopy”</em></div> <div> </div> <div>10:45 – 11:00<span style="white-space:pre"> </span>Questions<br /><br /></div> <div> </div> <div>11:00 – 11:45<span style="white-space:pre"> </span>Inauguration ceremony with, Professor Stefan Bengtsson, President and CEO of Chalmers </div> <div> </div> <div>11:45 – 12:00<span style="white-space:pre"> </span>Walk to Canyon at MC2 building</div> <div> </div> <div>12:00 – 13:30<span style="white-space:pre"> </span>Lunch buffé</div> <div> </div> <div>13:30 – 13:50<span style="white-space:pre"> </span>Lecture</div> <div> </div> <div>13:50 – 14:10<span style="white-space:pre"> </span>Lecture</div> <div> </div> <div>14:10 – 14:30<span style="white-space:pre"> </span>Lecture<br /><br /></div> <div> </div> <div>14:30 – 15:00<span style="white-space:pre"> </span>Coffee/Tea<br /><br /></div> <div> </div> <div>15:00 – 15:20<span style="white-space:pre"> </span>Lecture</div> <div> </div> <div>15:20 – 15:40<span style="white-space:pre"> </span>Lecture</div> <div> </div> <div>15:40 – 16:00<span style="white-space:pre"> </span>Lecture<br /><br /></div> <div> </div> <div>16:00 – 16:15<span style="white-space:pre"> </span>Coffee/Tea<br /><br /></div> <div> </div> <div>16:15 – 16:30<span style="white-space:pre"> </span>Jeol</div> <div> </div> <div>16:30 – 16:45<span style="white-space:pre"> </span>Gatan</div> <div> </div> <div>16:45 – 17:00<span style="white-space:pre"> </span>Nanomegas</div> <div> </div> <div>17:00 – 17:15<span style="white-space:pre"> </span>DENSSolutions</div> <div> </div> <div><br /></div> <div> </div> <div>19:00 <span style="white-space:pre"> </span>Dinner, Universeum</div> <div> </div> <div>​<br /></div>https://www.chalmers.se/en/departments/mc2/calendar/Pages/GCC-Symposium-2019.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/GCC-Symposium-2019.aspxAdvances and Challenges: van der Waals Heterostructures<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​Graphene Centre Symposium</p>​<div>The Graphene Centre at Chalmers invites you to an exciting symposium on emerging van der Waals heterostructures. <div>Leading scientists, including Steven Louie (University of Berkeley), Alexander Tartakovskii (University of Sheffield) and Rudolf Bratschitsch (Univeristy of Münster) will present recent breakthroughs and challenges in this technologically promising field of research.</div></div>https://www.chalmers.se/en/centres/gpc/calendar/Pages/COLL_Michael_Doser_190516.aspxhttps://www.chalmers.se/en/centres/gpc/calendar/Pages/COLL_Michael_Doser_190516.aspxGeneral Physics Colloquium: Experiments on antimatter at CERN<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​ Speaker: Michael Doser, CERNAbstract: To be announced.​ ​Coffee will be served outside PJ lecture hall before the lecture at 14.45.​ The colloquium starts at 15.15.</p>https://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Adam_Arvidsson_190517.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Adam_Arvidsson_190517.aspxAdam Arvidsson, Physics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Title of the doctoral thesis: &quot;Partial methane oxidation: insights from first principles and micro-kinetics calculations&quot;.</p><h2 class="chalmersElement-H2">Abstract: </h2> <div><span style="background-color:initial">Partial methane oxidation is a much-desired reaction with some intriguing challenges. Not only is there a need to activate methane and oxygen, but there is also a need to control the selectivity and prevent over-oxidation to thermodynamically more stable products, like carbon dioxide and water. In fact, this is so difficult that at many oil extraction sites, methane, which inevitably accompanies the welled crude oil, is today flared since gas-phase methane is too inconvenient to store and transport. </span></div> <div> </div> <div>In nature, there are enzymes that can partially oxidize methane to methanol at ambient pressure and temperature, although at a very slow rate. An often studied class of material with the potential of being an inorganic analogue to these enzymes are zeolites. Zeolites are a porous class of material that can readily be synthesized and that have been shown to convert methane to methanol at ambient conditions with a high selectivity, but with a low conversion. Unravelling the bottlenecks of this, as of yet, inefficient reaction, calls for an atomistic understanding of what is in fact controlling activity and selectivity of the catalysts at hand.</div> <div> </div> <div>In this thesis, zeolites and chemically related structures, zeotypes, are studied using first-principles calculations combined with micro-kinetic modelling. As a first step, a candidate for the active site in these materials, the [Cu-O-Cu]2+ motif, which is found primarily in the ZSM-5 zeolite, and its relevance for Cu, Ni, Co, Fe, Ag, and Au is investigated. Using a straightforward first-principles based micro-kinetic model, we find that this motif is only relevant for copper. Vibrational IR-spectra and temperature programmed desorption spectra are also calculated for monomer and dimer copper motifs in the ZSM-5 and SSZ-13 zeolites, and the results support experimental conclusions. When studying the continued reaction of methanol to dimethyl ether, large-scale trends in activity correlated to the acidity of the acid sites in three zeolite framework types have been determined, indicating that tuning acidity will change the selectivity between methanol and dimethyl ether.</div> <div> </div> <div>The partial oxidation of methane is also studied using molybdenum sulfide clusters, Mo6S8 . These small clusters enables studies of a wider reaction network, similar to the one in zeolites, where the oxygenated species are replaced by their sulfur-contaning counterparts. In this way, it allows investigation of the activity and selectivity towards methanethiol and dimethyl sulfide using different reaction mechanisms and different promoters. The reaction of methane with H2S is used when cleaning sour natural gas, which is why, in this case, H2S is used as the oxidant instead of oxygen. Our results show that the presence of some promoters on the sulfide clusters affect activity, while others affect selectivity. Furthermore, the results show that diffusion is important to include in the kinetic model.</div>https://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-N-Dashti.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-N-Dashti.aspxLinnaeus Coffee Seminar with Nastaran Dashti<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Title: TBASpeaker: Nastaran Dashti from Applied Quantum Physics laboratory​ at the Department of Microtechnology and Nanoscience, Chalmers</p><div>Coffee and cake will be served before the talk at 14.00</div> <div>Welcome!</div> <div></div>https://www.chalmers.se/en/departments/mc2/calendar/Pages/LC-Eleni-Diamanti.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/LC-Eleni-Diamanti.aspxLinnaeus Colloquium with Eleni Diamanti<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​Eleni Diamanti, CNRS, Université Pierre et Marie Curie, France</p><h5 class="chalmersElement-H5">​Abstrac​t:</h5> <div>TBA </div>https://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Nils_Odebo_190524.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Disputation_Nils_Odebo_190524.aspxNils Odebo Länk, Physics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Title of doctoral thesis: &quot;Optimization of resonant all-dielectric nanoparticles for optical manipulation and light management&quot;.​</p>​<br /><b>Abstract</b>: To be announced.https://www.chalmers.se/en/departments/mc2/calendar/Pages/GCCS-Wang-Yao.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/GCCS-Wang-Yao.aspxValley-spintronics in the moiré of van der Waals layered structures<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Grapehene Centre Seminar with Wang Yao, Department of Physics and Center of Theoretical and Computational Physics, The University of Hong Kong The Graphene Center at Chalmers (GCC) will organize a monthly GCC seminar on the recent advances in the field of graphene and 2D materials. The seminars will be on a monthly basis and will take place every last Monday in the month. ​ Welcome to attend!​</p><div><h5 class="chalmersElement-H5"><span>Abstract:</span></h5></div> <div>In semiconducting transition metal dichalcogenides monolayers, the band edge carriers are described by massive Dirac cones, located at K and -K corners (valleys) of the Brillouin zone. The valley dependent properties of these massive Dirac fermions have enabled versatile control of the valley pseudospin in monolayers. Van der Waals stacking of the 2D semiconductors into vertical layered structures is a powerful approach towards designer quantum materials that can combine and extend the exotic properties of the building blocks. Ubiquitous to these vdW heterostructures is the formation of moiré́ pattern due to the inevitable lattice mismatch and twisting between the layers. We show that, uniquely for the valley massive Dirac fermions, the moiré offers unprecedented opportunities for nanoscale patterning of electronic, optical, magnetic, and topological properties. We give examples including: (i) electrically switchable lateral superstructures of topological insulators; (ii) moiré excitons for programmable arrays of quantum emitters; (iii) flux superlattice in twisted homobilayer.​</div>https://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Sara_Nilsson_190528.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Licentiateseminar_Sara_Nilsson_190528.aspxSara Nilsson, Physics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​ Title of thesis: &quot;Single copper nanoparticle oxidation — studied by correlative optical and electron microscopy&quot;​</p>​<br /><strong>Abstract</strong>: To be announced.https://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-H-He.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-H-He.aspxLinnaeus Coffee Seminar with Hans He<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​Title: TBASpeaker: Hans He from Quantum Device Physics laboratory at the Department of Microtechnology and Nanoscience, Chalmers</p>​<span style="background-color:initial">Coffee and cake will be served before the talk at 14.00</span><div>Welcome!</div>https://www.chalmers.se/en/departments/physics/calendar/Pages/Swedish_Microfluids_4-5juni.aspxhttps://www.chalmers.se/en/departments/physics/calendar/Pages/Swedish_Microfluids_4-5juni.aspxTwo days of SMILS<p>Kemivägen 4,</p><p>​​We welcome you to join us for two days of SMILS — the gathering of Swedish researchers within the field of microfluidics in life science.​</p>​​The meeting will highlight ongoing research in the microfluidics field in Sweden, and serve as a platform for networking between PhDs, postdocs and Pls.The research will be highlighted via student presentations, and five invited speakers will give inspiring talks and contribute to stimulating discussions. All participating students and postdocs are invited to present their work as posters. https://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-D-Niepce.aspxhttps://www.chalmers.se/en/departments/mc2/calendar/Pages/LCS-D-Niepce.aspxLinnaeus Coffee Seminar with David Niepce<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Title: TBASpeaker: David Niepce from Quantum Technology laboratory​ at the Department of Microtechnology and Nanoscience, Chalmers</p>​<span style="background-color:initial">Coffee and cake will be served before the talk at 14.00</span><div>Welcome!</div>https://www.chalmers.se/en/centres/gpc/calendar/Pages/Gothenburg_Lise_Meitner_Award_2019.aspxhttps://www.chalmers.se/en/centres/gpc/calendar/Pages/Gothenburg_Lise_Meitner_Award_2019.aspxCeremony and lecture – Gothenburg Lise Meitner Award 2019<p>FB, lecture hall, Fysikgården 4, Fysik Origo</p><p>​​​ Regents’​ Professor Aust​en Angell at Arizona State University, USA, is the winner of the Gothenburg Lise Meitner Award 2019. He will visit the Gothenburg Physics Centre to receive the award and give the traditional award lecture in honour of the Austrian-Swedish physicist Lise Meitner. ​Professor Aust​en Angell receives the award &quot;For inventing the concept of fragility of glass-forming liquids.”  Refreshments will be served after the lecture.​</p><h3 class="chalmersElement-H3"><br /></h3> <div><a href="http://www.public.asu.edu/~caangell/" style="outline:0px">Austen Angell​</a><span style="background-color:initial">, born 1933 in Canberra, Australia, is currently Regents’ Professor at Arizona State University, <br />USA. </span><span style="background-color:initial">During his long career, he has worked mostly on liquids and glasses, but also published on geochemical, biophysical and battery electrolyte problems. </span><span style="background-color:initial">He currently makes a major effort in the energy storage and <img src="/SiteCollectionImages/Centrum/Fysikcentrum/Gothenburg%20Lise%20Meitner%20Award/Lise%20Meitner%20Award%202019/austenangel_1.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:150px;height:196px" /><br />conversion disciplines. </span><span style="background-color:initial">He has more than 500 publications and has received several awards – for example the “Outstanding reviewer” award by APS 2009 and the Galileo Galilei award by ISPE 2018. </span><span style="background-color:initial">I</span><span style="background-color:initial">n 2015 he was honored as University College London's Bragg lecturer. </span></div> <div> </div> <div></div> <div> </div> <div>Professor Angell holds a Ph.D. degree from London University, Imperial College, where he won the Armstrong medal for 1959-61. <span style="background-color:initial">He made a postdoc at Argonne National Laboratory, before joining Purdue University where he became full professor in 1971, and is at ASU since 1989. </span></div> <div><br /><div><a href="https://isearch.asu.edu/profile/20438">Read more about Austen Angell, Arizona State University</a></div> <div><a href="https://scholar.google.com/citations?user=A4EhbT0AAAAJ&amp;hl=en">Read more about his publications</a></div> <div><a href="https://www.public.asu.edu/~caangell/angellbiography.pdf">Read Austen Angell’s biography​</a></div></div> <div> </div>