Comparative Quantum Monte Carlo studies of the two-dimensional bond Su-Schrieffer-Heeger and Holstein models

Electron-phonon (e-ph) interactions play an important role in the understanding of conventional superconductivity. While the Holstein model has long provided a fruitful testbed for nonperturbative e-ph simulations, the community’s attention has recently shifted towards Su-Schrieffer-Heeger (SSH)-like models, where the atomic motion modulates the electron hopping. The shift has been driven by results suggesting that such couplings can produce light bipolarons and mediate high-T_c superconductivity. Here, we study and compare the two-dimensional bond-SSH and Holstein models using state-of-the-art hybrid and determinant Quantum Monte Carlo methods. Specifically, we perform a systematic comparison of the quasiparticle properties and pairing tendencies of both models as a function of model parameters, doping, and temperature.