“Quasiparticle Theory Revisited: Fragility and Anisotropy”

Dr. Seongjin Ahn
Department of Physics, Chungbuk National University

Oct. 20 (Fri.), 04:00 PM
https://kriss-re-kr.zoom.us/j/84862389983?pwd=F75QpsZMntobha20s30JG4HZyWbcjm.1

회의 ID: 848 6238 9983
암호: 694513

Abstract:
Landau quasiparticle theory is one of the greatest triumphs of solid-state physics since it drastically simplifies interacting many fermion problems into the much simpler single-particle Fermi gas problems. In this work, we explore the quasiparticle theory in more depth by looking into the previously neglected aspects of the theory, which are fragility and anisotropy. First, we discuss the robustness and limitations of the Fermi liquid quasiparticle description in 2D electron gas, showing that the basic Landau quasiparticle picture is reliable in a wide range of energy except for a small discrete region where quasiparticles are coupled with plasmon excitations. Second, we investigate the effect of electron-electron interactions on the shape of the Fermi surface in anisotropic 2D electron gas, finding that the Fermi surface deviates from an ellipse in only two distinct shapes with the elliptical Fermi-surface approximation still being valid in most cases.