Multigap s -wave superconductivity emerging in the 1T′ phase of MoTe2 under hydrostatic pressure

This is the authors' abstract. We don't add key points for this paper.

Hydrostatic pressure transforms the superconductor MoTe₂ from a type-II Weyl semimetallic Td phase to a topologically trivial 1T^' phase at low temperature, serving as an ideal platform to explore the interplay between topology and superconductivity (SC). We report a soft point-contact-spectroscopy (SPCS) study on single-crystalline MoTe₂ under hydrostatic pressure up to 2.5 GPa, where the local SC transition temperature Tc of MoTe₂ in the contact region shows the same behavior as the reported pressure phase diagram. Excess current extracted from the integrated conductance subtracted by the normal state shows a positive correlation with the 1T^' phase volume fraction as a function of pressure, supporting that the probed SC under pressure is mainly contributed by the 1T^' phase of MoTe₂. Our SPCS spectra are better fitted by a two-gap s-wave Blonder-Tinkham-Klapwijk model in the whole pressure range, yielding 2Δ₁/kBTc=2.0--2.5 and 2Δ₂/kBTc=4.15--5.0, respectively, and suggesting a strong-coupling SC for 1T^'-MoTe₂.