Excitation spectra and correlation functions of quantum Su-Schrieffer-Heeger models

Abstract

We study one-dimensional Su-Schrieffer-Heeger (SSH) models with quantum phonons using a continuous-time quantum Monte Carlo method. Within statistical errors, we obtain identical results for the SSH model with acoustic phonons, and a related model with a coupling to an optical bond phonon mode. Based on this agreement, we first study the Peierls metal-insulator transition of the spinless SSH model, and relate it to the Kosterlitz-Thouless transition of a spinless Luttinger liquid. In the Peierls phase, the spectral functions reveal the single-particle and charge gap, and a central peak related to long-range order. For the spinful SSH model, which has a dimerized ground state for any nonzero coupling, we reveal a symmetry-related degeneracy of spin and charge excitations, and the expected spin and charge gaps as well as a central peak. Finally, we study the SSH-$UV$ model with electron-phonon and electron-electron interaction. We observe a Mott phase with critical spin and bond correlations at weak electron-phonon coupling, and a Peierls phase with gapped spin excitations at strong coupling. We relate our findings to the extended Hubbard model, and discuss the physical origin of the agreement between optical and acoustic phonons.

12 pages, 13 figures

References in corpus (14)

• Classification of topological insulators and superconductors in three spatial dimensions
• Diagrammatic Determinantal methods: projective schemes and applications to the Hubbard-Holstein model
• Phase diagram of the one-dimensional half-filled extended Hubbard model
• Phase diagram of the one dimensional Hubbard-Holstein Model at 1/2 and 1/4 filling
• Excitation spectra and spin gap of the half-filled Holstein-Hubbard model
• Adiabatic-antiadiabatic crossover in a spin-Peierls chain
• Effect of Electron-Phonon Interaction Range for a Half-Filled Band in One Dimension
• The quantum vs classical aspects of one dimensional electron-phonon systems revisited by the renormalization group method
• Comment on ``Ground State Phase Diagram of a Half-Filled One-Dimensional Extended Hubbard Model''
• Nature of ground states in one-dimensional electron-phonon Hubbard models at half-filling
• Dynamic charge correlations near the Peierls transition
• Tomonaga-Luttinger parameters and spin excitations in the dimerized extended Hubbard model
• Phase diagram of the spin-Peierls chain with local coupling
• Phase diagram and isotope effects of the quasi-one-dimensional electron gas coupled to phonons

Cited by in corpus (7)

• Superconductivity, charge-density waves, antiferromagnetism, and phase separation in the Hubbard-Holstein model
• Reduced density matrix and order parameters of a topological insulator
• High-precision numerical solution of the Fermi polaron problem and large-order behavior of its diagrammatic series
• Phonon spectral function of the one-dimensional Holstein-Hubbard model
• Interplay of Site and Bond Electron-Phonon Coupling in One Dimension
• Continuous-time quantum Monte Carlo for fermion-boson lattice models: Improved bosonic estimators and application to the Holstein model
• Variational wave functions for the spin-Peierls transition in the Su-Schrieffer-Heeger model with quantum phonons