Superconductivity in doped symmetric mass generation insulator: a quantum Monte-Carlo study

TL;DR

This study uses sign-problem-free quantum Monte Carlo simulations to show that doping a symmetric mass generation insulator leads to robust superconductivity, with interactions enhancing the pairing, relevant to high-$T_c$ superconductors.

Contribution

It provides the first numerically exact evidence that doping a SMG insulator can induce and enhance superconductivity, offering a new paradigm for unconventional superconductivity.

Findings

Superconductivity emerges upon doping the SMG insulator.

Hubbard interactions significantly enhance SC order.

Results are relevant to high-$T_c$ superconductor $ ext{La}_3 ext{Ni}_2 ext{O}_7$.

Abstract

Understanding unconventional superconductivity (SC) driven by strong electronic correlations is a central challenge in condensed matter physics. In this work, we employ sign-problem-free quantum Monte Carlo (QMC) simulations to systematically investigate a bilayer fermionic model featuring strong interlayer antiferromagnetic (AFM) exchange and on-site repulsive Hubbard interactions. This system serves as a prototypical model for realizing a symmetric mass generation (SMG) insulator. Our numerically exact results unambiguously demonstrate that robust superconducting pairing emerges upon doping the SMG phase. Remarkably, we find that the SC order is significantly enhanced by the repulsive Hubbard interaction. Given its potential relevance to the essential features of the high-$T_c$ superconductor $\mathrm{La}_{3}\mathrm{Ni}_{2}\mathrm{O}_{7}$ under pressure, our study establishes a new paradigm for superconductivity arising from a doped SMG parent state and provides key theoretical guidance for future experimental investigations.