Quasi-two-dimensional superconductivity in 1$T$-Ti$_{1-x}$Ta$_x$Se$_2$

TL;DR

This study demonstrates quasi-two-dimensional superconductivity in bulk $1T$-Ti$_{1-x}$Ta$_x$Se$_2$, revealing weak interlayer coupling and a BKT transition, thus positioning it as a platform for low-dimensional superconducting physics.

Contribution

It provides the first comprehensive evidence of intrinsic quasi-2D superconductivity in bulk TMD crystals, confirmed by angle-dependent measurements and BKT transition observations.

Findings

Weakly coupled anisotropic superconductivity confirmed

Angle-dependent upper critical field measurements support 2D nature

Observation of Berezinskii-Kosterlitz-Thouless transition

Abstract

The emergence of two-dimensional (2D) superconductivity in bulk transition metal dichalcogenides (TMDs) is a fascinating area of research, as their weak interlayer coupling leads to novel superconducting behavior and offers a rich platform to host nontrivial gap structures and interactions with other electronic orders. In this work, we present a comprehensive study of the superconducting properties of bulk single-crystalline $1T$-Ti$_{1-x}$Ta$_x$Se$_2$ for x = 0.2. Our results confirm the weakly coupled anisotropic superconductivity. Angle-dependent upper critical field measurements and observation of a Berezinskii-Kosterlitz-Thouless transition confirm the quasi-2D nature of the superconducting state. These results position $1T$-Ti$_{1-x}$Ta$_x$Se$_2$ as a promising platform for exploring low-dimensional superconducting physics and highlight bulk TMD crystals as a promising platform for realizing intrinsic 2D superconductivity, opening avenues for future quantum applications.