Triplet $p+ip$ paring correlation in doped Kane-Mele-Hubbard model: A quantum Monte Carlo study

TL;DR

This study uses quantum Monte Carlo simulations to explore how doping affects pairing symmetries in the Kane-Mele-Hubbard model, revealing potential pathways to realize spin triplet superconductivity.

Contribution

It provides the first systematic analysis of pairing correlations in the doped Kane-Mele-Hubbard model using constrained-phase quantum Monte Carlo.

Findings

$d+id$ pairing dominates near half filling

$p+ip$ pairing dominates below three-quarters filling

Superconducting correlations are enhanced with increased interaction

Abstract

By using the constrained-phase quantum Monte Carlo method, we performed a systematic study of the pairing correlations in the ground state of the doped Kane-Mele-Hubbard model on a honeycomb lattice. We find that pairing correlations with $d+id$ symmetry dominate close to half filling, but pairing correlations with $p+ip$ symmetry dominate as hole doping moves the system below three-quarters filling. We correlate these behaviors of the pairing correlations with the topology of the Fermi surfaces of the non-interacting problem. We also find that the effective pairing correlation is enhanced greatly as the interaction increases, and these superconducting correlations are robust against varying the spin-orbit coupling strength. Our numerical results suggest a possible way to realize spin triplet superconductivity in doped honeycomb-like materials or ultracold atoms in optical traps.