Comparative determinant quantum Monte Carlo study of the acoustic and optical variants of the Su-Schrieffer-Heeger model

Journal Article · 18 October 2023 · Physical Review. B

DOI: https://doi.org/10.1103/physrevb.108.165138 · OSTI ID:2216888

Costa, Sohan Malkaruge  ^[1]; Cohen-Stead, Benjamin  ^[2]; Ly, Andy Tanjaroon  ^[2]; Neuhaus, James  ^[2]; Johnston, Steven  ^[2]

---

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

We compare the acoustic Su–Schrieffer–Heeger (SSH) model with two of its optical variants where the phonons are defined on either on the sites or bonds of the system. First, we discuss how to make fair comparisons between these models in any dimension by ensuring their dimensionless coupling λ and relevant phonon energies are the same. We then use determinant quantum Monte Carlo to perform nonperturbative and sign-problem-free simulations of all three models on one-dimensional chains at and away from half-filling. By comparing the results obtained from each model, we demonstrate that the optical and acoustic models produce near identical results within error bars for suitably chosen phonon energies and λ at half-filling. In contrast, the bond model has quantitatively different behavior due to its coupling to the q = 0 phonon mode. These differences also manifest in the total length of the chain, which shrinks for the bond model but not for the acoustic and optical models when λ ≠ 0. Furthermore, our results have important implications for quantum Monte Carlo modeling of SSH-like interactions, where these models are sometimes regarded as being interchangeable.

• Research Organization: University of Tennessee, Knoxville, TN (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
• Grant/Contract Number: SC0022311; AC05-00OR22725
• OSTI ID: 2216888
• Journal Information: Physical Review. B, Journal Name: Physical Review. B Journal Issue: 16 Vol. 108; ISSN 2469-9950
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English