Fermi Polarons in 2D semiconductors
Francesca Maria Marchetti, PhD
Universidad Autónoma de Madrid (UAM), 28049 Madrid, Spain
Présentation en anglais
Vidéoconférence, Zoom #: 826 4844 1097 (Zoom link)
Lorsque demandé, entrez: 852540
Abstract: The concept of “impurity problem” in quantum physics, i.e., few particles surrounded by a quantum gas, goes back to 1933, when the Russian physicist Lev Landau described the properties of conduction electrons in a dielectric medium. Here, polarons are quasi-particles resulting from the dressing of electrons by collective excitations of the dielectric medium. Despite nearly a century of work, the polaron problem continues to attract significant interest. In particular, recent ground-breaking experiments in ultracold atomic gases and semiconductor TMD monolayers have renewed interest in this topic. This seminar focuses on the properties of Fermi polarons in 2D semiconductors, the elementary optical excitations of a 2D electron (or hole) gas. These systems have the unique possibility of being embedded into optical cavities to allow strong coupling between matter and light, leading to the formation of polaritonic quasi-particles. After reviewing the literature, I will describe our recent results in this area [A. Tiene et al., https://arxiv.org/abs/2109.12994]. These consider the limit where the TMD monolayer is spin/valley polarised and the carriers in the Fermi sea are indistinguishable from one of the two carriers forming the optically generated exciton.
Bio: Francesca Maria Marchetti obtained her PhD in 2002 from Scuola Normale Superiore (Pisa, Italy). After a 4 year postdoctoral stay in Cambridge (in the group of Prof. Peter Littlewood and as an independent 3-yr EPSRC Postdoctoral Fellow) and a 2 year postdoctoral fellowship in Oxford with Prof. John Chalker and as an independent 5-yr EPSRC Advanced Fellow, Dr. Marchetti obtained a 3-yr tenure-track Ramon y Cajal Fellowship at UAM. Since 2013, Dr. Marchetti is a Professor at the Department of Theory of Condensed Matter at the Universidad Autónoma de Madrid (Spain). Prof. Marchetti’s research interests concern the fields of solid-state polaritons and degenerate gases of atoms. She has been working on aspects of collective phenomena in strongly correlated systems, macroscopic phase coherence, and superfluidity in and out of equilibrium. Her most important contributions have been on collective phases and superfluid properties of polariton microcavity heterostructures driven into different regimes. In the field of ultracold atoms, she contributed substantially on research about imbalanced mixtures of Fermi and Bose-Fermi gases, as well as on density-wave phases in fermionic gases with a permanent dipole moment.
Cette conférence est présentée par le RQMP.
