报告题目： Exotic Surface Properties of Delafossite PdCoO2 and PdCrO2
报告人：严智明教授 李政道研究所
报告时间：2025年9月26日上午10：00
报告地点：物理科技楼101室
报告邀请人：蒋密
报告摘要：Delafossite metals ABO₂ are known for their rich properties [1] and potential for realizing directional ballistic transport. This talk focuses on the surface properties of PdCoO₂ and PdCrO₂.
First, I will report on the STM findings from their oxide-terminated surfaces [2,3], particularly on a rarely observed short-range charge order formed on the CrO2-terminated surface of PdCrO2 that, owing to its fragility, can only be captured by imaging at extremely low-currents [3]. Our calculation results suggest that surface charge disproportionation is the underlying mechanism.
As for the Pd surfaces, both exhibits clear scattering signals in their pristine form. However, when the Pd surface of PdCrO2, which can be regarded as a 2D metal, is adsorbed with hydrogen, a tiling structure consisting of closely packed hydrogen clusters is formed. This arrangement of hydrogen also leads to strong electronic localization [4], as well as extremely long-lived vibrational modes.
报告人简介：Prof. Dr. Chi Ming Yim received his PhD degree from University College London (UK) in 2012, then pursued postdoctoral research at UCL and University of St Andrews (UK). In 2020, Chi Ming joined Tsung-Dao Lee Institute, Shanghai Jiao Tong University, where he leads a low temperature STM group to study the exotic phenomena in strongly correlated electron materials at the atomic length scale. Till now, Chi Ming has published 39 papers in journals including Nature Materials, Nature Communications, PNAS and PRL etc.
Chi Ming’s group website: https://web.tdli.sjtu.edu.cn/cmyim/
