报告题目 ：Theory of supercurrent in chiral Josephson junctions 

报告人：   胡金鑫 博士后 （新加坡南洋理工大学） 

报告时间：2024年7月17日（星期三）10：30-11：30

报告地点：北洋园校区 49 教 410 室 （线上：腾讯会议 838-9499-4192）

报告摘要：

Recently, several experiments reported that the magnetic field interference pattern of the quantum hall edge states mediated Josephson junctions can exhibit Fraunhofer oscillations with a periodicity of either h/e or h/2e. However, a unified understanding of such a phenomenon is still absent. In this talk, I will discuss the competition between crossed Andreev reflections and local Andreev reflections results in the crossover between h/e and h/2e quantum oscillations in chiral edge-channel Josephson junctions. Our theory explains why recent experiments observed either h/e or h/2e oscillations in different samples. Furthermore, we explain that when the chiral Andreev edge state couple, a pair of localized Majorana modes appear at the ends of the Josephson junction, which are robust and independent of the phase difference between the two superconductors. As the h/2e-periodicity and the Majorana zero modes have the same physical origin, the Fraunhofer oscillation period can be used to identify the regime with Majorana zero modes.

报告人简介：

      胡金鑫于2018年从中国科学技术大学获得学士学位，并于2023年在香港科技大学获得博士学位。目前，他在新加坡南洋理工大学从事博士后工作。他的研究方向包括二维材料，量子输运理论，以及非常规超导等。

参考文献：

[1] Jin-Xin Hu, et al. "Josephson diode effect induced by valley polarization in twisted bilayer graphene." Phys. Rev. Letters 130.26 (2023): 266003.

[2] Zi-Ting Sun, Jin-Xin Hu*, et al. " Anomalous h/2e-periodicity and Majorana zero modes in chiral Josephson junctions." Phys. Rev. Letters (in press).