Supercurrent diode effect and finite-momentum superconductors

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 a role analogous to spin.

Automated summary

When both inversion and time-reversal symmetries are broken, the critical current of a superconductor can be nonreciprocal. In this work, it is shown 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, resulting in unequal critical currents in the direction parallel and antiparallel to the Cooper pair momentum. This supercurrent diode effect is also observed in the polarity dependence of in-plane critical fields induced by a supercurrent. These nonreciprocal effects can be found in polar SrTiO3 film, few-layer MoTe2 in the Td phase, and twisted bilayer graphene where the valley degree of freedom plays a role analogous to spin.