Electron-Electron Interaction and Weak Antilocalization Effect in a Transition Metal Dichalcogenide Superconductor

TL;DR

This study investigates how electron-electron interactions and strong spin-orbit coupling influence weak antilocalization and superconductivity in a disordered transition metal dichalcogenide superconductor, revealing disorder-enhanced effects.

Contribution

It provides direct experimental evidence of disorder effects, electron-electron interactions, and spin-orbit coupling on transport properties in 1T-NbSeTe superconductor.

Findings

Resistivity upturn with T1/2 dependence at low temperature.

Magnetoresistance H1/2 dependence at high magnetic fields.

Observation of weak antilocalization effect due to strong SOC.

Abstract

In disordered transition-metal dichalcogenide (TMD) superconductor, both the strong spin-orbit coupling (SOC) and disorder show remarkable effects on superconductivity. However, the features of SOC and disorder were rarely detected directly. Here we report the quantum transport behaviors arising from the interplay of SOC and disorder in the TMD superconductor 1T-NbSeTe. Before entering the superconducting state, the single crystal at low temperature shows a resistivity upturn, which is T1/2 dependent and insensitive to the applied magnetic fields. The magnetoresistance (MR) at low temperatures shows a H1/2 dependence at high magnetic fields. The characteristics are in good agreement with the electron-electron interaction (EEI) in a disordered conductor. In addition, the upturn changes and MR at low magnetic fields suggest the contribution of weak antilocalization (WAL) effect arising from the strong SOC in the material. Moreover, the quantitative analyses of the transport features in different samples imply anomalous disorder-enhanced superconductivity that needs to be further understood. The results reveal the disorder enhanced EEI and the strong SOC induced WAL effect in 1T-NbSeTe, which illustrate the resistivity minimum in the widely studied doped superconductors. The work also provides insights into the disorder effect on the superconductivity.