# Topological Ising pairing states in monolayer and trilayer TaS$_2$

## TL;DR

This paper explores topological superconductivity in monolayer and trilayer TaS$_2$, identifying promising pairing states with unique nodal structures and potential for large-Chern-number phases under doping or pressure.

## Contribution

It introduces a novel gapless f+s-wave pairing state with mirror parity, explaining experimental observations and predicting new topological phases in layered TaS$_2$.

## Key findings

- Identifies a gapless f+s-wave pairing state with 12 or 36 nodes.
- Shows the state aligns with STM experimental results.
- Predicts large-Chern-number phases under doping or pressure.

## Abstract

We study the possibility of topological superconductivity in the noncentrosymmetric monolayer and trilayer TaS$_2$ with out-of-plane mirror symmetry. A gapless time-reversal invariant f+s-wave pairing state with even mirror parity is found to be a promising candidate. This mixing state holds 12(36) nodes at the Fermi pockets around $\Gamma$ for monolayer(trilayer) case and its unconventional superconductivity is consistent with the STM experiments observed in 2$H$-TaS$_2$ thin flakes. Furthermore, with doping or under uniaxial pressure for trilayer 2$H$-TaS$_2$, large-Chern-number time-reversal symmetry breaking mixing states between d+id- and p-ip-wave pairings can be realized in the phase diagram.