Spin and thermal conductivity in classical disordered spin chain

TL;DR

This study investigates how quenched disorder affects spin and thermal transport in a classical disordered spin chain, revealing a transition from insulating to conducting behavior at low temperatures and the impact of staggered fields on localization.

Contribution

It provides a detailed analysis of transport properties in a classical disordered spin chain, highlighting the crossover from insulator to conductor and the effects of additional staggered fields on localization.

Findings

Transport remains finite in the pure case due to nonintegrability.

Disorder causes a transition to insulating behavior at low temperatures.

Staggered fields enhance many-body localization effects.

Abstract

Transport quantities of the classical spin chain with the quenched disorder in the antiferromagnetic coupling $J_i$ are evaluated using the dynamical simulation at finite temperatures $T>0$ . Since the classical model is nonintegrable, spin and thermal conductivities remain finite even in the pure case. On the other hand, the role of disorder becomes crucial at low $T $ leading to a vanishing transport due to the Anderson localization within the linearized regime. The crossover from the insulator to the conductor appears both for the spin and thermal transport at quite low $T^* \ll J$. Still the many-body localization regime at $T>0$ evidenced by extremely short mean free paths can be strongly enhanced by introducing into the model an additional staggered field.