ABSTRACT
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.
BIOGRAPHY
Dr. Noah Fan Qi Yuan obtained his Ph. D. at the Hong Kong University of Science and Technology in 2017, and then went to Massachusetts Institute of Technology as a Postdoctoral Associate until 2020. His research interests are mainly unconventional superconductivity and two-dimensional materials, such as topological superconductivity, Ising superconductivity, gapless superconductivity, finite-momentum Cooper pairs, moiré superlattices, graphene systems and few-layer transition metal dichalcogenides.
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