Study of impurities in spin-Peierls systems including lattice relaxation

TL;DR

This paper investigates how impurities affect spin-Peierls systems, revealing the formation of magneto-elastic solitons and impurity-bound states, with implications for magnetic properties and lattice interactions.

Contribution

It introduces a comprehensive model including lattice relaxation and quantum fluctuations to analyze impurity effects in spin-Peierls systems, highlighting soliton formation and impurity binding mechanisms.

Findings

Strong bonds form near impurities, creating solitons.

Interchain coupling can bind solitons to impurities.

Small chain segments may lack magnetic moments at ends.

Abstract

The effects of magnetic and non-magnetic impurities in spin-Peierls systems are investigated allowing for lattice relaxation and quantum fluctuations. We show that, in isolated chains, strong bonds form next to impurities, leading to the appearance of magneto-elastic solitons. Generically, these solitonic excitations do not bind to impurities. However, interchain elastic coupling produces an attractive potential at the impurity site which can lead to the formation of bound states. In addition, we predict that small enough chain segments do not carry magnetic moments at the ends.