Nonadiabatic Approach to Spin-Peierls Transitions via Flow Equations

TL;DR

This paper introduces a nonadiabatic method for analyzing spin-Peierls transitions, replacing the traditional adiabatic approach, and predicts temperature-dependent couplings consistent with experimental observations.

Contribution

It develops a novel nonadiabatic framework that maps magneto-elastic problems to magnetic ones, showing the equivalence of solitons and spinons without soft phonons.

Findings

Magneto-elastic solitons are equivalent to magnetic spinons.

No soft phonon is necessary for the transition.

Temperature-dependent couplings match experimental data.

Abstract

The validity of the adiabatic approach to spin-Peierls transitions is assessed. An alternative approach is developed which maps the initial magneto-elastic problem to an effective magnetic problem only. Thus the equivalence of magneto-elastic solitons and magnetic spinons is shown. No soft phonon is required for the transition. Temperature dependent couplings are predicted in accordance with the analysis of experimental data.