Vertical quantum wire realized with double cleaved-edge overgrowth

TL;DR

This paper reports the fabrication and characterization of a quantum wire on GaAs created by double cleaved-edge overgrowth, demonstrating conductance quantization and 1D electron states at the corner.

Contribution

It introduces a novel method for creating a quantum wire using double cleaved-edge overgrowth on GaAs, with detailed electrical and optical characterization.

Findings

Conductance quantization observed in the wire.

Density and mobility characterized for both cleave facets.

Micro-photoluminescence indicates 1D electron states.

Abstract

A quantum wire is fabricated on (001)-GaAs at the intersection of two overgrown cleaves. The wire is contacted at each end to n+ GaAs layers via two-dimensional (2D) leads. A sidegate controls the density of the wire revealing conductance quantization. The step height is strongly reduced from 2e^2/h due to the 2D-lead series resistance. We characterize the 2D density and mobility for both cleave facets with four-point measurements. The density on the first facet is modulated by the substrate potential, depleting a 2um wide strip that defines the wire length. Micro-photoluminescence shows an extra peak consistent with 1D electron states at the corner.