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

Journal Article · 15 September 2024 · Physical Review. B

DOI: https://doi.org/10.1103/PhysRevB.110.115130 · OSTI ID:2441336

Costa, Sohan Malkaruge ^[1]; Cohen-Stead, Benjamin ^[2]; Johnston, Steven ^[2]

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1. University of Tennessee, Knoxville, TN (United States); University of Tennessee, Knoxville
2. University of Tennessee, Knoxville, TN (United States)

We perform sign-problem-free determinant quantum Monte Carlo simulations of the optical Su- Schrieffer-Heeger model on a half-filled honeycomb lattice. In particular, we investigate the model’s semi-metal (SM) to Kekulé Valence Bond Solid (KVBS) phase transition at zero and finite temper- atures 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. Furthermore, our results highlight the important role bond-stretching phonon modes play in the formation of KVBS order in strained graphene-derived systems.

• Research Organization: University of Tennessee, Knoxville, TN (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: AC05-00OR22725; SC0022311
• OSTI ID: 2441336
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 11 Vol. 110; ISSN 2469-9950
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English