时间：2022年8月4日（周四） 14:00-15:30

Time: 14:00-15:30, Thursday, August 4th, 2022

主持人: 西湖大学理学院PI 吴颉 博士

Host: Dr. Jie Wu, PI of School of Science, Westlake University

地点：西湖大学云栖校区5号楼一楼学术报告厅

Venue: Lecture Hall, 1st Floor, Building 5, Yunqi Campus

主讲嘉宾/Speaker：

王健 教授

北京大学物理学院量子材料科学中心

主讲人简介/Biography:

Jian Wang, Changjiang Distinguished Professor of China's Ministry of Education. He received Ph.D degree in condensed matter physics from Institute of Physics, Chinese Academy of Sciences in 2007. He won Sir Martin Wood China Prize(2015) and Outstanding Achievement Award for Research in Institutes of Higher Education of China (Young Scientists 2019).

讲座摘要/Abstract:

Quantum Griffiths singularity (QGS) reveals the profound influence of quenched disorder on superconductor-metal transitions. The main characteristic of QGS is the divergent critical exponent zν when approaching the quantum critical point. We firstly observed QGS in Ga films and subsequently it was detected in various 2D superconductors under perpendicular magnetic field, indicating the universality of QGS. Recently, we report the observation of QGS under both perpendicular and parallel magnetic field in 4-monolayer crystalline PdTe2 films. The studies on QGS in diverse 2D superconductors shed new light on the superconductor-metal transitions and may change the paradigm of quantum phase transitions. After decades of explorations, suffering from the subtle nature, whether a metallic ground state exists in a 2D superconducting system is a mystery. In high-Tc superconducting films with patterned nanopores, a robust intervening anomalous metallic state (i.e. quantum metal or Bose metal) characterized by resistance saturations at low temperatures is detected. In ultrathin crystalline PdTe2 films, the anomalous metallic state is revealed by using high quality filters. Furthermore, at ultralow temperatures the anomalous ground metallic state is uncovered in a 2D crystalline transition metal dichalcogenide superconductor (4Ha-TaSe2 flakes) although at higher temperatures the metallic state induced by the external noise is observed. Our findings offer the reliable evidences on the existence of anomalous quantum metallic ground states in 2D superconducting systems.

讲座联系人/Contact:

理学院 钟老师 zhongmengzhen@westlake.edu.cn