Giant rectification in segmented, strongly interacting, spin chains despite the presence of perturbations

TL;DR

This paper investigates giant spin current rectification in segmented, strongly interacting spin chains, revealing that significant rectification occurs due to energy gap formation, but perfect rectification is absent in the thermodynamic limit.

Contribution

It extends previous work to more general segmented chains with both integrable and non-integrable parts, showing giant rectification can occur even without ballistic transport.

Findings

Giant rectification occurs when the two halves are sufficiently different.

Energy gap emergence in the out-of-equilibrium steady state causes rectification.

No perfect rectification exists in the thermodynamic limit for interacting chains.

Abstract

In Phys. Rev. Lett. 120, 200603 (2018), a segmented XXZ spin chain with zero anisotropy in one half and a large anisotropy on the other half gave rise to a spin current rectification which is perfect in the thermodynamic limit. Here we extend the previous study to segmented chains with interacting integrable as well as non-integrable halves, considering even cases in which no ballistic transport can emerge in either half. We demonstrate that, also in this more general case, it is possible to obtain giant rectification when the two interacting half chains are sufficiently different. We also show that the mechanism causing this effect is the emergence of an energy gap in the excitation spectrum of the out-of-equilibrium insulating steady state in one of the two biases. Finally we demonstrate that in the thermodynamic limit there is no perfect rectification when each of the two half chains is interacting.