Anomalous quantized plateaus in two-dimensional electron gas with gate confinement

TL;DR

This paper reports unexpected quantized plateaus at anomalous fractions in a confined 2DEG, revealing larger filling factors and advancing understanding of edge states crucial for quantum Hall experiments.

Contribution

It demonstrates the existence of anomalous quantized plateaus in confined 2DEG, challenging previous assumptions about edge state behavior under confinement.

Findings

Observed quantized plateaus at fractions like 9/4, 17/11, 16/13, and 3/2.

Attributed these plateaus to larger filling factors in the confined region.

Provides insights into edge state behavior under gate confinement.

Abstract

Quantum information can be coded by the topologically protected edges of fractional quantum Hall (FQH) states. Investigation on FQH edges in the hope of searching and utilizing non-Abelian statistics has been a focused challenge for years. Manipulating the edges, e.g. to bring edges close to each other or to separate edges spatially, is a common and essential step for such studies. The FQH edge structures in a confined region are typically presupposed to be the same as that in the open region in analysis of experimental results, but whether they remain unchanged with extra confinement is obscure. In this work, we present a series of unexpected plateaus in a confined single-layer two-dimensional electron gas (2DEG), which are quantized at anomalous fractions such as 9/4, 17/11, 16/13 and the reported 3/2. We explain all the plateaus by assuming surprisingly larger filling factors in the confined region. Our findings enrich the understanding of edge states in the confined region and in the applications of gate manipulation, which is crucial for the experiments with quantum point contact and interferometer.