Novel metallic and insulating states at a bent quantum Hall junction

TL;DR

This study explores a non-planar quantum Hall junction with unique metallic and insulating states depending on the filling factor, revealing complex conductance behaviors and potential explanations through Hartree calculations.

Contribution

It introduces a novel bent quantum Hall junction geometry and analyzes its electronic states, highlighting differences from traditional planar structures and identifying new metallic and insulating regimes.

Findings

Metallic state at filling factor nu=1/3 with conductance increasing as temperature decreases

Strongly insulating behavior at nu=1, 2

Weak temperature dependence at nu=3, 4

Abstract

A non-planar geometry for the quantum Hall (QH) effect is studied, whereby two quantum Hall (QH) systems are joined at a sharp right angle. When both facets are at equal filling factor nu the junction hosts a channel with non-quantized conductance, dependent on nu. The state is metallic at nu = 1/3, with conductance along the junction increasing as the temperature T drops. At nu = 1, 2 it is strongly insulating, and at nu = 3, 4 shows only weak T dependence. Upon applying a dc voltage bias along the junction, the differential conductance again shows three different behaviors. Hartree calculations of the dispersion at the junction illustrate possible explanations, and differences from planar QH structures are highlighted.