报告问题 (Title)：General Theory of Josephson Diodes（约瑟夫森二极管效应的理论研究）

报告人 (Speaker)：张燚 特聘副研究员（8188cc威尼斯）

报告时间 (Time)：2022年12月2日 (周五) 10:00-12:00

报告所在 (Place)：线下校本部E408、线上腾讯聚会（聚会ID：458-852-806）

约请人(Inviter)：物理系青联

主理部分：理学院物理系

报告摘要： Motivated by recent progress in the superconductivity nonreciprocal phenomena, we study the general theory of Josephson diodes. The central ingredient for Josephson diodes is the asymmetric proximity process inside the tunneling barrier. From the symmetry breaking point of view, there are two types of Josephson diodes, inversion breaking and time-reversal breaking. For the inversion breaking case, applying voltage bias could effectively tune the proximity process like the voltage-dependent Rashba coupling giving rises to I_c (V)≠I_c (-V). For the time-reversal breaking case, the magnetic field and current flow could adjust the internal time-reversal breaking field like magnetism or time-reversal breaking electron-electron pairing, which leads to I_c (B)≠I_c (-B) or I_(c+)≠I_(c-). All these results provide a complete understanding and the general principles of realizing Josephson diodes, especially the recently found NbSe2/Nb3Br8/NbSe2 Josephson diodes.