Phenomenology of the 0.7 conductance feature

TL;DR

This paper presents a phenomenological model explaining the 0.7 conductance feature in quantum point contacts, aligning well with experimental data and highlighting key conditions for microscopic theories.

Contribution

It introduces a simple phenomenological model for the 0.7 conductance feature that matches experimental results and guides future microscopic theory development.

Findings

Model agrees with experimental transconductance data

Highlights boundary conditions for microscopic theories

Contrasts with single-particle picture

Abstract

We describe a phenomenological model for the conductance feature near $0.7 \times 2e^2/h$ that occurs in quantum point contacts. We focus on the transconductance at finite source-drain bias and contrast our model with the results expected from a single-particle picture. Good agreement is seen in comparing the model with experimental data, taken on ultra-low-disorder GaAs induced electron systems. Although simple, our phenomenology suggests important boundary conditions for an underlying microscopic theory.