Two-Fold Anisotropic Superconductivity in Bilayer T$_d$-MoTe$_2$
Abstract
Noncentrosymmetric 2D superconductors with large spin-orbit coupling offer an opportunity to explore superconducting behaviors far beyond the Pauli limit. One such superconductor, few-layer T-MoTe, has large upper critical fields that can exceed the Pauli limit by up to 600%. However, the mechanisms governing this enhancement are still under debate, with theory pointing towards either spin-orbit parity coupling or tilted Ising spin-orbit coupling. Moreover, ferroelectricity concomitant with superconductivity has been recently observed in the bilayer, where strong changes to superconductivity can be observed throughout the ferroelectric transition pathway. Here, we report the superconducting behavior of bilayer T-MoTe under an in-plane magnetic field, while systematically varying magnetic field angle and out-of-plane electric field strength. We find that superconductivity in bilayer MoTe exhibits a two-fold symmetry with an upper critical field maxima occurring along the b-axis and minima along the a-axis. The two-fold rotational symmetry remains robust throughout the entire superconducting region and ferroelectric hysteresis loop. Our experimental observations of the spin-orbit coupling strength (up to 16.4 meV) agree with the spin texture and spin splitting from first-principles calculations, indicating that tilted Ising spin-orbit coupling is the dominant underlying mechanism.
Keywords
Cite
@article{arxiv.2409.09308,
title = {Two-Fold Anisotropic Superconductivity in Bilayer T$_d$-MoTe$_2$},
author = {Zizhong Li and Apoorv Jindal and Alex Strasser and Yangchen He and Wenkai Zheng and David Graf and Takashi Taniguchi and Kenji Watanabe and Luis Balicas and Cory R. Dean and Xiaofeng Qian and Abhay N. Pasupathy and Daniel A. Rhodes},
journal= {arXiv preprint arXiv:2409.09308},
year = {2024}
}