报告题目：Gate-defined Josephson junction and diode effect in twisted bilayer graphene

报告人： 胡金鑫 博士（香港科技大学）

报告时间：2023年5月19日(周五) 10：30-12：00

报告地点：北洋园校区32教140室

报告摘要：

Recently, the Josephson diode effect (JDE), in which the superconducting critical current magnitudes differ when the currents flow in opposite directions, has attracted great interest. In particular, it was demonstrated that gate-defined Josephson junctions based on magic-angle twisted bilayer graphene showed a strong nonreciprocal effect when the weak-link region is gated to a correlated insulating state at half-filling (two holes per moiré cell). We show that the interaction-driven valley polarization, together with the trigonal warping of the Fermi surface, induce the JDE. The valley polarization, which lifts the degeneracy of the states in the two valleys, induces a relative phase difference between the first and the second harmonics of supercurrent and results in the JDE.

报告人简介：

2014-2018, 中国科学技术大学物理系, 学士。

2018-2023, 香港科技大学, 博士。