Interference and zero-bias anomaly in tunneling between Luttinger-liquid wires

TL;DR

This paper combines theoretical and experimental work to demonstrate the Luttinger-liquid behavior in coupled quantum wires, revealing interference effects, spin-charge separation, and boundary influences on conductance properties.

Contribution

It provides the first combined theoretical and experimental analysis of Luttinger-liquid effects in tunneling between quantum wires, highlighting boundary effects and methods to extract interaction parameters.

Findings

Observation of conductance oscillation modulation due to spin-charge separation

Boundary effects influence Luttinger-liquid exponents

Temperature dependence of conductance dip reveals interaction parameters

Abstract

We present theoretical calculations and experimental measurements which reveal the Luttinger-liquid (LL) nature of elementary excitations in a system consisting of two quantum wires connected by a long narrow tunnel junction at the edge of a GaAs/AlGaAs bilayer heterostructure. The boundaries of the wires are important and lead to a characteristic interference pattern in measurements on short junctions. We show that the experimentally observed modulation of the conductance oscillation amplitude as a function of the voltage bias can be accounted for by spin-charge separation of the elementary excitations in the interacting wires. Furthermore, boundaries affect the LL exponents of the voltage and temperature dependence of the tunneling conductance at low energies. We show that the measured temperature dependence of the conductance zero-bias dip as well as the voltage modulation of the conductance oscillation pattern can be used to extract the electron interaction parameters in the wires.