Events: Fysik events at Chalmers University of TechnologyThu, 21 Mar 2019 15:33:04 +0100 optical absorption and luminescence in hBN: a tool for a characterisation metrics from bulk to the monolayer​<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>Graphene Centre Seminar with Annick Loiseau, LEM, CNRS - Onera, France​ Coffee and cake will be served from 12:40 outside Kollektorn.  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">​Abstrac​t:</h5> <div><div>hBN layers meet a growing interest for deep UV LED [1], and has become a strategic material for the fabrication of van der Waals heterostructures. Stacked with any other 2D material it can reveal the best of their physical properties [2]. However, hBN optoelectronic properties remain much less characterized and understood than other 2D materials.</div> <div><span style="background-color:initial">In this talk, we review recent advances made thanks to the development of appropriate spectroscopies in the UV range - cathodoluminescence  (CL) at 4K and Raman [3,4], angular resolved EELS [5] combined with ab initio simulations and tight binding modeling [6]. Thanks to these tools, a h-BN characterization metrics has been developed on the basis of their original optical properties, governed, in the energy range 5.5 – 6 eV, by strong excitonic effects easily trapped at structural or chemical defects [3]. We shall discuss the interplay between structure, defects and spectroscopic properties and how these properties can be further exploited for sample benchmarking [3, 7].</span></div> <div><span style="background-color:initial">Beyond this effort, the talk will also address the recent advances made for the understanding of the high luminescence observed although bulk hBN is an indirect band gap material [1,8,9]. To that aim, the efficiency of radiative recombinations has been measured on a reference single crystal using temperature - dependent CL and compared to that diamond and ZnO [10]. The luminescence of hBN is confirmed to be unusually high and is found to remain constant from 10 to 300K. Enlighting analysis of this behaviour is provided by ab initio calculations of the exciton dispersion in bulk hBN. First, the lowest-energy exciton (iX) is found at 5.97eV and to be indirect, as expected for an indirect band gap, with a binding energy equal to 300 meV. This dispersion behavior accounts for an assignation of the luminescence to phonon assisted recombinations of the indirect exciton as proposed in [11] and for the assignation of the tiny peak observed in CL spectra at 5.956 eV to the zero-phonon radiative recombination of iX [10]. Further iX high binding energy is consistent with the temperature behavior of the luminescence, the high yield being the signature of a strong exciton phonon coupling. Second, calculations also confirm the direct exciton (dX) with a binding energy of 670 meV [10], an energy which turns to be only 100 meV above the indirect one. It comes out that bulk hBN displays a peculiar behavior where luminescence and optical absorption are due to different excitons, one resonant and one non resonant [10]. </span></div> <div><br /></div> <div>[1] K. Watanabe et al Nature Mat, 3 (2004), 404</div> <div>[2] C. R. Dean et al., Nature Nanotech, 5, 722 (2010). </div> <div>[3] L. Schué et al., 2D Mat., 4, 015028 (2017)</div> <div>[4] I. Stenger et al., 2D Mat., 4, 031003 (2017).</div> <div>[5] F. Fossard et al, Phys. Rev. B96, 115304 (2017)</div> <div>[7] L. Schué et al., Nanoscale, 8 (2016), 6986</div> <div>[8] B. Arnaud et al, Phys. Rev. Lett., 96 (2006), 026402</div> <div>[9] L. Sponza, et al, Phys. Rev. B, 97 (2018), 075121</div> <div>[10] L. Schué et al, arXiv:1803.03766v1 [cond-mat.mtrl-sci], Phys. Rev. Lett. In press (2019) </div> <div>[11] G. Cassabois et al, Nature Photonics 10, 262 (2016)</div></div> Nanophotonics Symposium<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>A common platform open to all researcher interested in nanophotonics. Come and learn about the activities that are happening in Gothenburg.  Everybody is more than welcome to attend!</p><h3 class="chalmersElement-H3">​Programme:</h3> <div><span style="background-color:initial">09.00-09.20</span><span style="background-color:initial;white-space:pre"> </span><span style="background-color:initial">Introduction: Ruggero Verre</span></div> <div> </div> <div>09.20-09.40<span style="white-space:pre"> </span>Langhammer´s group (Physics, Chalmers): Ievgen Nedrygailov</div> <div> </div> <div>09.40-10.00<span style="white-space:pre"> </span>Dalhin’s group (Chemistry, Chalmers): Oliver Olsson</div> <div> </div> <div>10.00-10.20<span style="white-space:pre"> </span>Volpe´s group (Physics, GU): Falko Shmidt<br /><br /></div> <div> </div> <div>10.20-11.00<span style="white-space:pre"> </span>Coffee Break<br /><br /></div> <div> </div> <div>11.00-11.20<span style="white-space:pre"> </span>Shegai´s group (Physics, Chalmers): Denis Baranov</div> <div> </div> <div>11.20-11.40<span style="white-space:pre"> </span>Erhart’s group (Physics, Chalmers): Tuomas Ruossi</div> <div> </div> <div>11.40-12.00<span style="white-space:pre"> </span>Dmitriev’s group (Physics, GU): Esteban Pedrueza</div> Day and Diploma ceremony for Best thesis award<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​​Welcome to listen to the presentations by our to be promoted colleagues at the Department of Physics.</p><div><h4 class="chalmersElement-H4" style="font-family:&quot;open sans&quot;, sans-serif">Schedule<br /><span style="font-weight:700;background-color:initial;font-size:14px">14.40</span><span style="background-color:initial;font-size:14px"> Coffee and cake will be served outside PJ lecture hall.<br /></span><span style="font-weight:700;background-color:initial;font-size:14px">15.00</span><span style="background-color:initial;font-size:14px"> </span><span style="background-color:initial;font-size:14px">Welcome by Thomas Nilsson.<br /><strong>15.05-15.15</strong> Diploma ceremony for<a href="/en/departments/physics/news/Pages/They-know-how-to-write-a-doctoral-thesis-with-flow.aspx"> Best PhD Thesis Award 2018​</a>.<br /><strong>Awarded:</strong> Sophie Viaene and Ferry Nugroho <br /><br /><strong>Promotion lectures:</strong></span></h4> <div><span style="background-color:initial"><span style="font-weight:700">​15.15 Christoph Langhammer</span></span><span style="background-color:initial">, </span><span style="background-color:initial"> for the title as P</span><span style="background-color:initial">rofessor.</span><span style="background-color:initial"><br /></span></div></div> <div><a href="">Abstract of talk: When one is more than many​​</a><br /><br /><span style="background-color:initial"><span style="font-weight:700">15.35 Paul Erhart</span>, </span><span style="background-color:initial"> for the title as P</span><span style="background-color:initial">rofessor.</span><br /></div> <div><a href="">Abstract of talk: Predictive modeling of transport properties​​</a><br /><br /></div> <div><span style="font-weight:700;background-color:initial">16.00 Björn Wickman</span><span style="background-color:initial">,</span><span style="background-color:initial"> </span><span style="background-color:initial">for the title as &quot;oavlönad Docent&quot;.</span><span style="background-color:initial"><br /></span><a href="/en/departments/physics/calendar/Pages/promotion_lecture_Bjorn_Wickman_190326.aspx">Abstract of talk: Electrocatalysis for energy and environment​​​</a><span style="background-color:initial"><br /></span></div> one is more than many<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Promotion lecture by Christoph Langhammer, for the title as Professor, Department of Physics.​</p><h4 class="chalmersElement-H4">​Abstract: </h4> <div><span style="background-color:initial">Nanoparticles are the key functional elements in numerous technologies, ranging from sensors and drug <img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/ChristophLanghammer.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:152px;height:197px" /><br />delivery to heterogeneous catalysis. In experimental studies of such systems large ensembles comprised of millions of particles are typically analyzed. The corresponding ensemble averaging thus significantly blurs our vision when attempting to establish structure-function correlations. </span></div> <div> </div> <div>In my lecture I will therefore discuss the value of single nanoparticle spectroscopy and present some of our recent advances in this context related to the fields of metal-hydrogen interactions, metal oxidation and heterogeneous catalysis.</div> modeling of transport properties<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Promotion lecture by Paul Erhart, for the title as Professor, Department of Physics.​</p><h4 class="chalmersElement-H4">​Abstract:<br /></h4> <div><div>Thermal and electrical transport properties are crucial for practically all energy related technologies. <img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/Paul%20Erhart.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:173px;height:194px" /><br />The ability to predict these properties is therefore very valuable for the design of new and the continued development of established materials.</div> <div><span style="background-color:initial"><br />I</span><span style="background-color:initial"> will describe how thermal and electrical conductivities can be calculated from first-principles calculations and discuss various scattering mechanisms active in real materials. Finally, I will indicate opportunities for future developments in methodology and applications.</span><br /></div> <div>​<br /></div></div> for energy and environment<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Docent lecture by Björn Wickman, for the title as &quot;oavlönad docent&quot; at the Department of Physics. ​ ​​</p><h4 class="chalmersElement-H4">​Abstract: <br /></h4> <div><span style="background-color:initial">​Electrocatalytic reactions are central in applications such as fuel cells and hydrogen production via water <img src="/SiteCollectionImages/Institutioner/F/Blandade%20dimensioner%20inne%20i%20artikel/Bjorn_W.jpg" class="chalmersPosition-FloatRight" alt="" style="margin:5px;width:145px;height:189px" /><br />splitting. These techniques are also likely to become vital parts of a more sustainable energy system. To realize this, new and improved catalyst materials need to be developed. To this end, my research strives to understand the detailed reaction mechanisms as well as the intrinsic (electro)catalytic properties of catalyst materials for low temperature fuel cells and hydrogen production. In addition, I will also present a new method that relies on electrochemically induced alloy formation, to remove toxic heavy metals from water.​</span></div>'s thesis presentation: Anders Furufors<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​T​itle of Master&#39;s thesis: : Network implementation in an FPGA</p><h4 class="chalmersElement-H4">​Abstract:</h4> <div>A limited network stack is implemented on an FPGA for use in nuclear <span style="background-color:initial">physics experiments to transfer data directly from front-end electronics to </span><span style="background-color:initial">a PC over Ethernet. This is done using an FPGA board equipped with a </span><span style="background-color:initial">c</span><span style="background-color:initial">onnector</span><span style="background-color:initial"></span><span style="background-color:initial"> attached to a PHY chip. Code was written for this FPGA to </span><span style="background-color:initial">handle the physical and most of the link layer. Higher layers of network </span><span style="background-color:initial">communication were implemented in the FPGA, using a hardware design </span><span style="background-color:initial">called Fakernet. Fakernet handles the rest of the link layer as well as network </span><span style="background-color:initial">and transport layer protocols.</span></div> <div> </div> <div><br /></div> <div> </div> <div>This results in a design that sufficiently handles protocols needed for estab<span style="background-color:initial">lishing</span><span style="background-color:initial"></span><span style="background-color:initial"> a connection between nodes on a network (ICMP, ARP) and to be </span><span style="background-color:initial">c</span><span style="background-color:initial">onfigured</span><span style="background-color:initial"></span><span style="background-color:initial"> using a UDP interface. It is able to send data to a PC using TCP, </span><span style="background-color:initial">reaching line speed with the PHY chip’s 100 Mb/s interface while at the </span><span style="background-color:initial">same time having low resource usage, occupying less than 2 per cent of the </span><span style="background-color:initial">LUTs of an FPGA used in the type of experiment the design is considered </span><span style="background-color:initial">f</span><span style="background-color:initial">or. This design was tested for various situations and restrictions and it is </span><span style="background-color:initial">concluded that it has potential for being used in real experiments in the future </span><span style="background-color:initial">even though Fakernet is not yet fully developed.</span></div> on heterogeneous catalysis<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p></p><h3 class="chalmersElement-H3">The lecturers:<br /></h3> <div><div><div><span>Michail Stamatakis, Department of Chemical Engineering, UCL</span><br /><a href=""><span style="background-color:initial">​</span>​<img src="/_layouts/images/icgen.gif" class="ms-asset-icon ms-rtePosition-4" alt="" /> “Multiscale Modelling and Synergy with Experiments towards a Fundamental Understanding of Heterogeneous Catalysts”​​</a></div></div> <em> </em><p class="chalmersElement-P"><br /></p> <em> </em><div><span>Francesc Illas, Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computatcional, Universitat de Barcelona</span><br /></div> <div><a href=""><span style="background-color:initial">​</span>​​<img src="/_layouts/images/icgen.gif" class="ms-asset-icon ms-rtePosition-4" alt="" /> “Morphology, Stability, and Electronic Properties of Stoichiometric realistic TiO2 Nanoparticles”​</a></div> <em> </em><p class="chalmersElement-P"><br /></p> <em> </em><div><span>Lars Österlund, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University​</span><br /></div> <div><a href=""><span style="background-color:initial">​</span>​​<img src="/_layouts/images/icgen.gif" class="ms-asset-icon ms-rtePosition-4" alt="" />​ “Photo-adsorption of small molecules on wide bandgap oxides: SO2, NO2 and CO2 photo-fixation on TiO2”​</a></div></div> <div> </div> <div></div> Jørgensen, Physics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Title of doctoral thesis:​ Kinetic Simulations of Nanoparticle Catalysis from First Principles</p><h3 class="chalmersElement-H3">Abstract:</h3> <div><span style="background-color:initial">Understanding reactions on nanoparticles can save energy and provide cleaner air. This might seem like a bold statement at first; but did you know that nanoparticles are used in about 90% of the chemical industry, and are the main actors in cleaning exhaust from cars?</span></div> <div> </div> <div>The technological devices used for automotive exhaust treatment are called catalysts. Catalysts are composed of nanoparticles that transform toxic gases, such as CO, into less harmful chemicals such as CO2 . Such a transformation takes place on the surface of the nanoparticle, which has been researched for over a 100 years. Catalysts are often composed of scarce metals, such as platinum, palladium, and gold; and even small improvements in efficiency can have huge impacts on a global scale. Despite the efforts to understand what characterizes an efficient catalyst, the technology is often developed by trial and error. This is partly because catalyst nanoparticles are smaller than the wavelength of visible light and can only be seen using electron microscopes. Therefore, understanding how chemical reactions proceed over nanoparticles is an achievement that can have tremendous consequences for global pollution control and chemical technology. Today, computers are so powerful that it is possible to perform computer experiments solely on the screen. Computer simulations have the advantage that we directly can address causes and effects. Such insights may help answer the tough question: How do we arrange and combine the atoms in nanoparticles to design a cheap, efficient, and sustainable catalyst?</div> <div> </div> <div>In this thesis, I delve into developing and performing computer simulations to understand chemical reactions on the surface of nanoparticles. The computer simulations are performed over simple, yet, realistic nanoparticles, as they appear in an electron microscope. I give examples of methods developed to perform the computer simulations, the information we can extract from them, and how the simulations relate to real experiments.</div> <div> </div> <div>The simulations revealed that the chemistry of the individual atoms that make up the nanoparticle is quite different from the chemistry of the combined system. That is, the system behaves differently than the sum of its parts. This information helped finding interesting relations between catalytic efficiency/effectiveness and particle shape and size. While the methods and results in this thesis helps understanding chemical reactions on nanoparticles, more investigations are required to disentangle the complex chemistry of nanoparticle catalysis. Ultimately, we may be able to design a sustainable future, atom by atom.​</div> Physics Colloquium by Stefano Vitale<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Title of talk: Gravitational wave astronomy within ESA Science Programme​ Colloquium by Stefano Vitale from LISA mission,  University of Trento, Italy ​Coffee will be served outside PJ lecture hall from 14.45.​ The colloquium starts at 15.15.​</p><div><h4 class="chalmersElement-H4">Abstract: </h4> <div>The talk reports on the international effort to develop the space-borne gravitational wave observatory known as LISA. In particular it will review the science case for such an observatory, particularly in the context of ESA's science programme. It will then report on the results from LISA's precursor LISA Pathfinder, which has been successfully flown by the European Space Agency (ESA) in 2015-17. Finally the talk will illustrate the status of LISA development within an international collaboration led by ESA, and including several of ESA member states and NASA.</div></div> Day at the Science Festival<p>Vasa A, lecture hall, Vera Sandbergs Allé 8, Vasa Hus 2-3 entréhall</p><p>​​Fysikens dag är ​Fysikcentrums årliga bidrag på Vetenskapsfestivalens öppna program. Välkommen till en inspirerande temadag fullspäckad med intressanta föredrag. Du bjuds på en inblick i den senaste forskningen inom flera av fysikens områden och möjlighet att ställa dina kluriga frågor till våra forskare.​</p><h2 class="chalmersElement-H2">​<br /><span>Programme Saturday 6 April, 2019</span></h2> <div><b>Moderatorer:</b> <span style="background-color:initial"> C</span><span style="background-color:initial">hristian Forssén och Fredrik Höök, professorer, institutionen för fysik, Chalmers.</span></div> <span></span><div><br />Note that all the lectures will be held in Swedish.​<br /></div> <div> </div> <div><br /></div> <div> </div> <div><b>10.00 – 10.40 </b><span style="background-color:initial"><b>Att skriva, läsa och verkställa livets program</b></span></div> <div> </div> <div><i>Anna Reymer, forskare, kemi, Chalmers</i><br /></div> <div> </div> <div><div>DNA bär på koden som instruerar varje aspekt av våra liv: hur proteiner – livets byggstenar – görs, samt de instruktioner som reglerar alla andra biologiska processer. Hur verkställs det här programmet, hur kan det modifieras och hur leder olika ändringar i mjukvaran till skador eller till och med förbättringar?</div> <div><br /><div><b>10.40 - 11.10 Fikapaus</b></div> <div></div> <div>Fysikcentrum Göteborg bjuder alla besökare på kaffe och bulle.​</div> <br /></div></div> <div> </div> <div><b>11.10 – 12.30 Fotosyntesen, våra sinnen och kvantdatorer</b></div> <div> </div> <div><i>Fredrik Höök, professor, Fysik, och Göran Johansson, professor på Mikroteknologi och nanovetenskap, Chalmers</i></div> <div> </div> <div>Livet på jorden drivs av fotosyntesen, en process som är nära besläktad med vår syn, och involverar biologi, kemi och kvantfysik. Med inspiration från biologisk evolution kommer vi ha en diskussion som rör sig från fotosyntes via våra sinnen till drömmen om häpnadsväckande kvantdatorer.​</div> <div> </div> <div><br /></div> <div> </div> <div><b>14.00 – 14.40 Nya grundämnen i det periodiska systemet</b></div> <div> </div> <div><span style="background-color:initial"><i>Ulrika Forsberg, doktor, Lunds universitet</i><div>Så sent som år 2016 lades fyra nya grundämnen till i det periodiska</div> <div>systemet: nihonium, moskovium, tenness och oganesson. Hur upptäcktes dessa och vad vet vi egentligen om dem? Vilka är de största utmaningarna i forskningen och vilka är våra förhoppningar inför framtiden?</div> <div><br /></div></span></div> <div> </div> <div><b>14.45 – 15.25 </b><span style="background-color:initial"><b>Stor, större, störst... De nya teleskopen</b></span></div> <div><span style="background-color:initial"><i>Kirsten Kraiberg Knudsen, biträdande professor, Rymd-, geo- och miljövetenskap, Chalmers</i><br /></span></div> <div> </div> <div><div>Om man ska observera avlägsna stjärnor och galaxer, så ska man inte bara ha </div> <div>ett stort teleskop, utan det behövs också smarta lösningar hur teleskopen byggs. </div> <div>Vi berättar om nya internationella radio- och optiska teleskop, </div> <div>och 'why size matters'. ​</div></div> <div></div> <div> </div> <div><br /></div> <div> </div> <div><b>15.30 – 16.10 Einsteinföreläsning</b></div> <div> </div> <div>Varje år håller en hemlig gäst ett föredrag till minne av Albert Einsteins Nobelföreläsning i Göteborg. </div> <div> </div> <div><br /></div> <div> </div> <h4 class="chalmersElement-H4">Welcome to attend!</h4> <div> </div> Jago, Physics<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>​ T​itle of doctoral thesis: &quot;Spatiotemporal carrier dynamics in graphene</p>​<br /><strong>Abstract:</strong> To be announced<br /> 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><strong><br />Ab​stract: </strong>To be announced Centre Seminar with Christoph Stampfer<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>​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. ​ Lecturer: Christoph Stampfer, Aachen, Germany Welcome to attend!</p><h5 class="chalmersElement-H5">​Abstra​ct:</h5> <div>TBA</div> Physics Colloquium by Federico Capasso<p>PJ, lecture hall, Fysikgården 2B, Fysik Origo</p><p>Speaker: Federico Capasso, Harvard University, USA Title: Flat optics with metasurfaces​ Abstract: To be announced.​ ​Coffee will be served outside PJ lecture hall from 14.45.​ The colloquium starts at 15.15.</p> 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> Centre Seminar with Wang Yao<p>Kollektorn, lecture room, Kemivägen 9, MC2-huset</p><p>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. ​ Lecturer: ​Wang Yao, Hong Kong Welcome to attend!​</p><div><h5 class="chalmersElement-H5"><span>Abstract:</span></h5></div> <div>TBA</div>