Single-electron Transport Through Quantum Point Contact

TL;DR

This paper uses numerical methods to analyze single-electron transport in quantum point contacts, revealing controllable current directions under realistic conditions and quantized Hall effects.

Contribution

It introduces a combined self-consistent Thomas-Fermi and time-dependent Schrödinger approach to study electron transport in quantum point contacts under quantum Hall conditions.

Findings

Current direction can be controlled externally.

Transport properties are consistent with quantum Hall effects.

Spatial distribution of current channels is characterized.

Abstract

Here, we employ a numerical approach to investigate the transport and conductance characteristics of a quantum point contact. A quantum point contact is a narrow constriction of a width comparable to the electron wavelength defined in a two-dimensional electron gas (2DEG) by means of split-gate or etching technique. Their properties have been widely investigated in the experiments. We define a quantum Hall based split-gate quantum point contact with standard gate geometry. Firstly, we obtain the spatial distribution of incompressible strips (current channels) by applying a self consistent Thomas-Fermi method to a realistic heterostructure under quantized Hall conditions. Later, time-dependent Schrodinger equation is solved for electrons injected in the current channels. The transport characteristics and time-evolutions are analyzed in the integer filling factor regime ({\nu} = 1) with the single electron density. The results confirm that the current direction in a realistic quantum point contact can be controllable with the external interventions.