A seminar series in condensed matter physics. The seminars take place every other Tuesday during the spring term.
Speaker: Simone Latini, DTU
Title of the lecture: "Designing Quasi-Particles of Light and Photo-Groundstates"
See abstract below.
Overview
- Date:Starts 9 May 2023, 10:15Ends 9 May 2023, 11:15
- Location:PJ seminar room
- Language:English
Abstract:
Progress of light-based technology has led to a paradigm shift in materials design: light, which has been commonly relegated to a mere probe of material properties, can be instead exploited to alter material properties altogether. Central in the paradigm shift is the possibility of generating strong coupling between light and matter and in turn induce the formation of light-matter hybrid states with properties which can be controlled on demand. An intriguing route to achieve strong light-matter coupling is to embed materials inside cavities, where the coupling is enhanced by the confinement of light in a small region of space. In the talk, I will present theoretical results based on first-principles methods on three different hybrid light-matter designs. I will demonstrate the formation of exciton-light hybrid states in 2D crystals embedded in a cavity and the tunability over their energetics and brightness [1]. I will then show how the strong light-matter coupling allows for the design of a three-way exciton-phonon-photon quasiparticle which is characterized by unique features in optical response [2]. Finally, I will introduce the concept of a photo-groundstate by demonstrating that the vacuum fluctuations of light can induce a change of the collective phase from paraelectric to ferroelectric in the groundstate of SrTiO3 (see Fig. adapted from [3]), which has thus far only been achieved in out-of equilibrium strongly excited conditions. These findings demonstrate the potential of cavity material engineering as a new paradigm for material manipulation.
[1] S. Latini, E. Ronca, U. de Giovannini, H. Hübener, and A. Rubio. Nano Letters 19, 3473-3479 (2019). DOI: 10.1021/acs.nanolett.9b00183
[2] S. Latini, U. de Giovannini, E. J. Sie, N. Gedik, H. Hübener, and A. Rubio. Physical Review Letters 126, 227401 (2021). DOI: 10.1103/PhysRevLett.126.227401
[3] S. Latini, D. Shin, S. Sato, C. Schäfer, U. de Giovannini, H. Hübener, and A. Rubio. PNAS 118, e2105618118 (2021). DOI: 10.1073/pnas.2105618118
