报告题目: Supercurrent diode effect and finite momentum superconductivity

报告摘要： When both inversion and time-reversal symmetries are broken, the critical current of a superconductor can be nonreciprocal. In this work we show that in certain classes of two-dimensional superconductors with antisymmetric spin-orbit coupling, Cooper pairs acquire a finite momentum upon the application of an in-plane magnetic field, and as a result, critical currents in the direction parallel and antiparallel to the Cooper pair momentum become unequal. This supercurrent diode effect is also manifested in the polarity-dependence of in-plane critical fields induced by a supercurrent. These nonreciprocal effects may be found in polar SrTiO3 film, few-layer MoTe2 in the Td phase, and twisted bilayer graphene in which the valley degree of freedom plays the role analogous to spin.

报告人简介：Noah F. Q. Yuan got his Ph. D. from the Hong Kong University of Science and Technology in 2017, and then went to MIT as a postdoc in Liang Fu’s group. He is mainly interested in superconductivity and two-dimensional materials, and has been working on topological superconductivity, moiré superlattices, supercurrent diode effect and other related topics.

主持 联系人：路建明 jmlu@pku.edu.cn