Field-induced Peierls order in systems of S=1 Heisenberg spins coupled to quantum phonons

Abstract

A spin-Peierls order emerges in a one-dimensional S=1 Heisenberg antiferromagnetic model with single-ion anisotropy, coupled to finite frequency bond phonons, in a magnetic field. Our results indicate that for the pure Heisenberg model, any Peierls transition is suppressed by quantum fluctuations of the phonon field. However, a magnetic field-induced spin-Peierls order is realized in the presence of strong single-ion anisotropy. Contrary to the standard Peierls state, the periodicity of bond strength modulation in this field-induced spin-Peierls state is variable and depends on the strength of the applied field. The nature of the ground state in this new phase and the associated field-driven transitions to and out of this phase are explored using extensive numerical simulations. In particular, we explore the spin and bond correlations and the evolution of bond order modulation with varying magnetic field.