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

Abstract

In disordered transition‐metal dichalcogenide (TMD) superconductor, both the strong spin‐orbit coupling (SOC) and the disorder show remarkable effects on superconductivity. However, the features of SOC and disorder are rarely detected directly. Herein, the quantum transport behaviors arising from the interplay of SOC and disorder in the TMD superconductor 1T‐NbSeTe are reported. Before entering the superconducting state, the single crystal at low temperature shows a resistivity upturn, which is T 1/2 dependent and insensitive to the applied magnetic fields. The magnetoresistance (MR) at low temperatures shows an H 1/2 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 the 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 illustrates the resistivity minimum in the widely studied doped superconductors. The work also provides insights into the disorder effect on superconductivity.

Planar Hall Effect and Quasi ‐ 2D Anisotropic Superconductivity in Topological Candidate 1T‐NbSeTe

“…Notably, a similar broad superconducting transition has been reported in a previous study involving both a polycrystalline sample and multiple single crystals of NbSeTe. [ 23,24 ] The broader transition can be attributed to the disorder resulting from the random occupation of the Se/Te sites.…”

“…The electrical resistivity versus temperature measurement 𝜌(T) was performed without an applied magnetic field over a temperature range of 300 to 1.1 K. The results are shown in multiple single crystals of NbSeTe. [23,24] The broader transition can be attributed to the disorder resulting from the random occupation of the Se/Te sites.…”

“…These phenomena primarily stem from the high spin‐orbit coupling induced by its topological surface state and disorder. [ 23 ] The coexistence of superconductivity and weak antilocalization is rare, and only a few compounds have been observed to exhibit such behavior. [ 23 ] Therefore, NbSeTe offers a unique opportunity to investigate superconductivity in topological semimetals and explore the intricate interplay between strong spin‐orbit coupling, disorder, and superconductivity in superconducting topological semimetals.…”

“…The disorder is believed to be important in suppressing and enhancing the superconductivity of 1 T ‐NbSeTe. [ 23,24 ] Recent studies have shown that controlled disorder can enhance the superconducting transition temperature in monolayer NbSe 2 and bulk 2 H ‐TaSe$$_{2-x}$$ S x by suppressing competing electronic orders, such as CDW. [ 25–28 ] These studies suggest that the disorder improved the strength of electron−phonon coupling.…”

Two-Dimensional Dielectrics for Future Electronics: Hexagonal Boron Nitride, Oxyhalides, Transition-Metal Nitride Halides, and Beyond

“…When the first 2D material, graphene, was isolated, − the nanoelectronics community was very excited, and it ignited the investigation of graphene and many other 2D materials. ,− The graphene thickness measures less than half a nanometer with exceptionally high electronic mobility as an important materials parameter for the transistor channel. Unfortunately, graphene is not suitable for MOSFETs because it is a semimetal and does not have a bandgap, giving rise to an unacceptable source-to-drain leakage current. , Fortunately, other 2D materials like transition-metal dichalcogenides (TMDs) and their derivatives emerged as suitable 2D materials for transistor channels. − While many challenges remain, after a decade of research, transistors made with 2D materials as channel materials have been fabricated with promising characteristics. − …”