Magnetic Field Enhanced Superconductivity in Epitaxial Thin Film WTe2

Tomoya Asaba; Yongjie Wang; Gang Li; Ziji Xiang; Colin Tinsman; Lu Chen; Shangnan Zhou; Songrui Zhao; David Laleyan; Yi Li; Zetian Mi; Lu Li

doi:10.1038/s41598-018-24736-x

Magnetic Field Enhanced Superconductivity in Epitaxial Thin Film WTe₂

Sci Rep. 2018 Apr 25;8(1):6520. doi: 10.1038/s41598-018-24736-x.

Authors

Tomoya Asaba¹, Yongjie Wang², Gang Li¹, Ziji Xiang¹, Colin Tinsman¹, Lu Chen¹, Shangnan Zhou¹, Songrui Zhao², David Laleyan², Yi Li³, Zetian Mi², Lu Li⁴

Affiliations

¹ Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
² Department of Electrical and Computer Engineering, McGill University, Montreal, Quebec, H3A 0E9, Canada.
³ Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MA, USA.
⁴ Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA. luli@umich.edu.

Abstract

In conventional superconductors an external magnetic field generally suppresses superconductivity. This results from a simple thermodynamic competition of the superconducting and magnetic free energies. In this study, we report the unconventional features in the superconducting epitaxial thin film tungsten telluride (WTe₂). Measuring the electrical transport properties of Molecular Beam Epitaxy (MBE) grown WTe₂ thin films with a high precision rotation stage, we map the upper critical field H_c2 at different temperatures T. We observe the superconducting transition temperature T _c is enhanced by in-plane magnetic fields. The upper critical field H_c2 is observed to establish an unconventional non-monotonic dependence on temperature. We suggest that this unconventional feature is due to the lifting of inversion symmetry, which leads to the enhancement of H_c2 in Ising superconductors.