Electron spins interaction in the spin-Peierls phase of the organic spin chain (o -DMTTF) 2 X (X = Cl, Br, I)

TL;DR

This study explores electron spin interactions in the spin-Peierls phase of (o-DMTTF)2X organic chains, revealing defect-induced solitons, their pairing behavior, and observing Rabi oscillations relevant for quantum information applications.

Contribution

It provides new insights into the spin dynamics, defect effects, and soliton behavior in the spin-Peierls phase of (o-DMTTF)2X, including experimental observation of Rabi oscillations.

Findings

Identification of spin gap temperature dependence during phase transition

Observation of magnetic solitons localized at defects

Detection of Rabi oscillations in solitons and soliton dimers

Abstract

We investigate the electron spin resonance of the organic spin-Peierls chain (o-DMTTF)2X with X = Cl, Br and I. We describe the temperature dependence of the spin gap during the phase transition and quantify the dimerization parameter $\delta$. At the lowest temperatures, the susceptibility is governed by defects in the spin dimerized chain. Such strongly correlated defects are the consequence of breaks in the translational symmetry of the chain. In the vicinity of the defects the spins are polarized antiferomagnetically forming a magnetic soliton: a spin 1 2 quasi-particle of size ruled by $\delta$ pinned to the defects. For (o-DMTTF)2Br and (o-DMTTF)2Cl, we show that the one-half of the total number of solitons are in isolation (as singles) whereas the other half form pairs (soliton dimers)with a strong magnetic coupling. The Rabi oscillations of both the single-soliton and the soliton-dimer are observed, which is a prerequisite in the context of quantum information.