Magnetotunneling as a Probe of Luttinger-Liquid Behavior

TL;DR

This paper proposes a new tunneling measurement method to detect Luttinger-liquid behavior in quantum wires by analyzing conductance dependence on voltage and magnetic field, revealing spin-charge separation.

Contribution

It introduces a novel experimental approach using magnetotunneling to probe the spectral function of Luttinger liquids, enabling direct observation of spin-charge separation.

Findings

The method can distinguish Luttinger-liquid spectral features.

Singularities in the I-V characteristic indicate spin-charge separation.

Feasibility of experimental implementation is discussed.

Abstract

A novel method for detecting Luttinger-liquid behavior is proposed. The idea is to measure the tunneling conductance between a quantum wire and a parallel two-dimensional electron system as a function of both the potential difference between them, $V$, and an in-plane magnetic field, $B$. We show that the two-parameter dependence on $B$ and $V$ allows for a determination of the characteristic dependence on wave vector $q$ and frequency $\omega$ of the {\it spectral function}, $A_{\rm LL}(q,\omega)$, of the quantum wire. In particular, the separation of spin and charge in the Luttinger liquid should manifest itself as singularities in the $I$-$V$-characteristic. The experimental feasibility of the proposal is discussed.