量子物質科學協同創新中心seminar & 低維量子物理國家重點實驗室 & 物理系seminar

報告題目： Theory of high temperature superconductivity of monolayer FeSe on the STO substrate and the transport theory of 2D superconductors 報告人：李定平教授 beat365物理系報告時間： 2016-6-27 16:00 報告地點：理科樓三樓報告廳（C302）摘要： Part one: Pairing in one atomic layer thick two dimensional electron gas by a single at band of high energy longitudinal optical phonons is considered. The polar dielectric SrTiO3 (STO) exhibits such an energetic phonon mode and the 2DEG is created both when one unit cell FeSe layer is grown on its (100) surface and on the interface with another dielectric like LaAlO3 (LAO). We obtain a quantitative description of both systems by solving the gap equation for Tc for arbitrary Fermi energy, electron-phonon coupling and the phonon frequency, and direct (RPA) electron-electron repulsion strength. The high temperature superconductivity in 1UCFeSe/STO is possible due to a combination of three factors: high LO phonon frequency, large electron-phonon coupling and huge dielectric constant of the substrate suppression the Coulomb repulsion.
Part two: We use Ginzburg-Landau theory to study the transport of 2D superconductors. Based on improved Gaussian variational approximation, we calculate the transition temperature and superfluid density. Using time dependent Ginzburg Landau theory, we obtain the IV curve and magneto resistance. Then We compare the theoretical results with the experimental data. 個人簡介：工作領域：高溫超導理論，特别是二類超導體渦旋物态物理性質的研究；波色愛因斯坦凝聚理論；多體量子理論和場論方法的研究；量子霍爾效應。
科研成果：李定平教授近年來對高溫超導體渦旋态和BEC相關領域進行了系統研究，已發表SCI收錄論文數篇，其中包括Reviews of Modern Physics 1篇，Physical Review Letters 4篇, Physical Review B 14篇，Physical Review A 4篇, Nuclear Physics B 4篇，Physics Letters B 2篇.