Kekulé valence bond order in the honeycomb lattice optical Su-Schrieffer-Heeger Model and its relevance to Graphene

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Main Authors: Costa, Sohan Malkaruge, Cohen-Stead, Benjamin, Johnston, Steven
Format: Preprint
Published: 2024
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author Costa, Sohan Malkaruge
Cohen-Stead, Benjamin
Johnston, Steven
author_facet Costa, Sohan Malkaruge
Cohen-Stead, Benjamin
Johnston, Steven
contents We perform sign-problem-free determinant quantum Monte Carlo simulations of the optical Su-Schrieffer-Heeger (SSH) model on a half-filled honeycomb lattice. In particular, we investigate the model's semi-metal (SM) to Kekul{é} Valence Bond Solid (KVBS) phase transition at zero and finite temperatures as a function of phonon energy and interaction strength. Using hybrid Monte Carlo sampling methods we can simulate the model near the adiabatic regime, allowing us to access regions of parameter space relevant to graphene. Our simulations suggest that the SM-KVBS transition is weakly first-order at all temperatures, with graphene situated close to the phase boundary in the SM region of the phase diagram. Our results highlight the important role bond-stretching phonon modes play in the formation of KVBS order in strained graphene-derived systems.
format Preprint
id arxiv_https___arxiv_org_abs_2407_09366
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Kekulé valence bond order in the honeycomb lattice optical Su-Schrieffer-Heeger Model and its relevance to Graphene
Costa, Sohan Malkaruge
Cohen-Stead, Benjamin
Johnston, Steven
Strongly Correlated Electrons
Statistical Mechanics
We perform sign-problem-free determinant quantum Monte Carlo simulations of the optical Su-Schrieffer-Heeger (SSH) model on a half-filled honeycomb lattice. In particular, we investigate the model's semi-metal (SM) to Kekul{é} Valence Bond Solid (KVBS) phase transition at zero and finite temperatures as a function of phonon energy and interaction strength. Using hybrid Monte Carlo sampling methods we can simulate the model near the adiabatic regime, allowing us to access regions of parameter space relevant to graphene. Our simulations suggest that the SM-KVBS transition is weakly first-order at all temperatures, with graphene situated close to the phase boundary in the SM region of the phase diagram. Our results highlight the important role bond-stretching phonon modes play in the formation of KVBS order in strained graphene-derived systems.
title Kekulé valence bond order in the honeycomb lattice optical Su-Schrieffer-Heeger Model and its relevance to Graphene
topic Strongly Correlated Electrons
Statistical Mechanics
url https://arxiv.org/abs/2407.09366