Layer Pseudospin Superconductivity in Twisted MoTe$_2$

TL;DR

This paper investigates the layer pseudospin-driven unconventional superconductivity in twisted bilayer MoTe$_2$, revealing how external fields can tune pairing states and induce finite-momentum pairings, with implications for understanding spin-valley physics.

Contribution

It introduces a minimal two-orbital layer-pseudospin model to analyze superconducting pairing mechanisms and predicts field-tunable finite-momentum pairings in twisted MoTe$_2$.

Findings

Interlayer pairing dominates in spin-valley-polarized states.

Intralayer pairing prevails in spin-valley-unpolarized states.

Weak displacement fields can stabilize finite-momentum pairings.

Abstract

Recent experiments have observed signatures of spin-valley-polarized unconventional superconductivity in twisted bilayer MoTe$_2$ (tMoTe$_2$). Here, we explore the rich physics of superconducting tMoTe$_2$, enabled by its unique layer-pseudospin structure. Within a minimal two-orbital layer-pseudospin model framework, both interlayer and intralayer Cooper pairings can be effectively visualized using a layer-space Bloch sphere representation. Remarkably, we find that interlayer pairing prevails in the spin-valley-polarized state, whereas intralayer pairing dominates in the spin-valley-unpolarized state. Strikingly, we further predict that for spin-valley-polarized intravalley superconducting state, experimentally feasible weak displacement fields can stabilize finite-momentum pairings at low temperatures. Additionally, in-plane magnetic fields, which break three-fold rotational symmetry, induce field-direction-dependent finite-momentum pairing states, leading to a versatile momentum-selection phase diagram. Our work highlights the crucial role of layer pseudospin in tMoTe$_2$'s unconventional superconductivity and demonstrates its unique tunability via external fields.