Superconductivity in twisted transition metal dichalcogenide homobilayers

TL;DR

This paper investigates the universal mechanism behind superconductivity in twisted WSe2 bilayers, suggesting a common boson-mediated pairing process that is independent of twist angle and layer polarization.

Contribution

It introduces a continuum band structure model and proposes a universal boson-mediated pairing mechanism in twisted WSe2 bilayers, supported by consistent experimental observations.

Findings

Intervalley intralayer pairing dominates

Effective attraction strength is consistent across samples

Pairing mechanism likely independent of twist angle

Abstract

For the first time, robust superconductivity has been independently observed in twisted WSe$_2$ bilayers by two separate groups [Y. Xia et al., arXiv:2405.14784; Y. Guo et al., arXiv:2406.03418.]. In light of this, we explore the possibility of a universal superconducting pairing mechanism in twisted WSe$_2$ bilayers. Using a continuum band structure model and a phenomenological boson-mediated effective electron-electron attraction, we find that intervalley intralayer pairing predominates over interlayer pairing. Notably, despite different experimental conditions, both twisted WSe$_2$ samples exhibit a comparable effective attraction strength. This consistency suggests that the dominant pairing glue is likely independent of the twist angle and layer polarization, pointing to a universal underlying boson-induced pairing mechanism.