报告题目：Charge Density Wave Order of The Superconducting Kagome Metals AV3Sb5
报告人：Hengxin Tan (Weizmann Institute of Science, Israel)
报告时间：2022年1月13日 10:00-12:00
报告地点：江湾校区一号交叉楼A5005
腾讯会议：387-052-546
摘要：The recently discovered kagome materials AV3Sb5 (A=K, Rb, Cs) attract great attention due to their abundant properties including the intriguing charge density wave (CDW), unconventional superconductivity, as well as nontrivial band topology. Experiments found that the materials experience a translational symmetry breaking in the temperature range of 80~100 K, which is accompanied by an in-plane 2*2 charge modulation. However, basic knowledge of the crystal and electronic structures of the CDW phase is absent. The origin of the CDW is also elusive. In this presentation, I will focus on the CDW phase of AV3Sb5 from theory. A brief review of the recent experiments about these materials is given first. Then I will show that the 2*2 charge modulation is best described by the so-called inversed star of David (ISD) structure instead of the hypothetical star of David (SD) pattern, which is supported by both the existing and subsequent experiments. The Fermi energy is found to be very close to the van Hove singularity. The origin of the CDW is thus discussed based on the Fermi surface nesting as characterized by the bare electronic susceptibility. Besides, the CDW order decreases the density of states at the Fermi energy, which may lead to a reduction for superconducting temperature T$_c$. The contribution of the electron-phonon coupling to T$_c$ is also estimated.
