Spin-catalyzed hopping conductivity in disordered strongly interacting quantum wires

TL;DR

This paper investigates how charge disorder affects transport in one-dimensional strongly interacting quantum wires within the spin-incoherent regime, revealing a novel hopping mechanism mediated by neutral modes.

Contribution

It introduces a new understanding of charge localization and spin protection in disordered SILL systems, highlighting unconventional energy transport via neutral phonon modes.

Findings

Charge excitations are localized by disorder.

Spin excitations remain delocalized and act as a heat bath.

Energy is transported mainly by neutral phonon modes.

Abstract

In one-dimensional electronic systems with strong repulsive interactions, charge excitations propagate much faster than spin excitations. Such systems therefore have an intermediate temperature range [termed the "spin-incoherent Luttinger liquid'" (SILL) regime] where charge excitations are "cold" (i.e., have low entropy) whereas spin excitations are "hot." We explore the effects of charge-sector disorder in the SILL regime in the absence of external sources of equilibration. We argue that the disorder localizes all charge-sector excitations; however, spin excitations are protected against full localization, and act as a heat bath facilitating charge and energy transport on asymptotically long timescales. The charge, spin, and energy conductivities are widely separated from one another. The dominant carriers of energy are neither charge nor spin excitations, but neutral "phonon" modes, which undergo an unconventional form of hopping transport that we discuss. We comment on the applicability of these ideas to experiments and numerical simulations.