Superconductivity and nonreciprocal transport in a type-II Weyl Semimetal Td- MoTe₂

Abstract

Superconductivity exists widely in materials, and electrons can be transported without energy-loss inside the superconductor. In most materials, flipping the direction of the magnetic field and current does not significantly influence the transport properties of the material. Broken symmetry in crystals offers a lot of phys-ical phenomena of nonreciprocity, such as ferroelectricity and second harmonic generation. One interesting phenomenon is magnetochiral anisotropy, where the electrical resistance depends on the direction of magnetic field. An ideal superconducting diode exhibits superconductivity in one direction and metallicity in the other direction. We report a significant magnetochiral anisotropy phenomenon with an extreme magnetochiral anisotropy coefficient γ up to 1 × 10⁹T⁻¹A⁻¹in a superconducting type-II Weyl semimetal Td-MoTe₂ as well as the rectification efficient η ≈1 and superconducting diode coefficient δ ≈0.1. We demonstrate a nonreciprocal charge transport measured in both DC and AC current. In-plane superconducting anisotropy is reported as well. The result opens a new route to the application of superconducting diodes under a relatively weak magnetic field in practice.

Date of Award	2022
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Ning WANG (Supervisor) & Dapeng YU (Supervisor)