Investigating the current distribution of parallel-configured quantum point contacts under quantum Hall conditions

TL;DR

This study models charge transport in quantum point contacts under quantum Hall conditions, revealing how magnetic fields and gate voltages influence current distribution and symmetry breaking at low temperatures.

Contribution

It provides a self-consistent computational approach to analyze charge density and potential in quantum Hall systems with metallic gates, highlighting the effects of magnetic fields and gate voltages.

Findings

Magnetic fields break spatial symmetry of current distribution.

Gate voltages influence scattering processes.

Charge distribution depends on magnetic field and gate voltage strengths.

Abstract

Electric-field-controlled charge transport is a key concept of modern computers, embodied namely in field effect transistors. The metallic gate voltage controls charge population, thus it is possible to define logical elements which are the key to computational processes. Here, we investigate a similar system defined by metallic gates inducing quasi-one-dimensional transport channels on a high-mobility electron system in the presence of a strong perpendicular magnetic field. Firstly, we solve the three-dimensional Poisson equation, self-consistently imposing relevant boundary conditions, and use the output as an initial condition to calculate charge density and potential distribution in the plane of a two-dimensional electron system, in the presence of an external magnetic field. Subsequently, we impose an external current and obtain the spatial distribution of the transport charges, considering various magnetic field and gate voltage strengths at sufficiently low (< 10 Kelvin) temperatures. We show that magnetic field breaks the spatial symmetry of the current distribution, whereas voltage applied to metallic gates determines the scattering processes.