题    目：Quantum Geometry and the Electron-Phonon Coupling

报 告 人：Jiabin Yu （于家斌）     Princeton University

时    间：2023年05月25日（星期四) 10：30

线上直播#腾讯会议号： 987 947 999

报告摘要：Electron-phonon coupling (EPC) is crucial for various phases of matter, particularly superconductivity. Previous studies of the bulk EPC strength did not consider the electron band geometry or topology. We find that the electron band geometry (like the Fubini-Study metric or its orbital-selective version) contributes to the dimensionless EPC constant in graphene and MgB2. The geometric contributions account for approximately 50% and 90% of the total EPC constant in graphene and MgB2, respectively. The geometric contributions in the two systems are further bounded from below by the topological contributions, which come from the winding numbers of nodal points/lines or the effective Euler number. Given that MgB2 is a phonon-mediated superconductor with a critical temperature of about 39K, our results suggest that the nontrivial electron band geometry/topology might favor superconductivity with a relatively high critical temperature.

报告人介绍：Dr. Yu got his Ph.D. from the Pennsylvania State University, University Park in 2020. Then, he spent two years as a postdoctoral fellow at the Condensed Matter Theory Center at the University of Maryland, College Park. He is currently a Moore postdoctoral fellow in the Department of Physics at Princeton University.