Coulomb drag between two spin incoherent Luttinger liquids

TL;DR

This paper investigates Coulomb drag in two parallel quantum wires within the spin incoherent Luttinger liquid regime, revealing how temperature-induced loss of $2k_F$ oscillations affects drag behavior and exploring effects of disorder.

Contribution

It introduces a model for Coulomb drag in spin incoherent Luttinger liquids and analyzes the crossover from low to high temperature regimes with implications for experiments.

Findings

Loss of $2k_F$ oscillations at $T > J$ alters drag temperature dependence.

Non-monotonic Coulomb drag behavior can occur due to thermal effects.

Weak disorder influences Coulomb drag and experimental measurements.

Abstract

In a one dimensional electron gas at low enough density, the magnetic (spin) exchange energy $J$ between neighboring electrons is exponentially suppressed relative to the characteristic charge energy, the Fermi energy $E_F$. At non-zero temperature $T$, the energy hierarchy $J \ll T \ll E_F$ can be reached, and we refer to this as the spin incoherent Lutinger liquid state. We discuss the Coulomb drag between two parallel quantum wires in the spin incoherent regime, as well as the crossover to this state from the low temperature regime by using a model of a fluctuating Wigner solid. As the temperature increases from zero to above $J$ for a fixed electron density, the $2k_F$ oscillations in the density-density correlations are lost. As a result, the temperature dependence of the Coulomb drag is dramatically altered and non-monotonic dependence may result. Drag between wires of equal and unequal density are discussed, as well as the effects of weak disorder in the wires. We speculate that weak disorder may play an important role in extracting information about quantum wires in real drag experiments.