Characterization of individual layers in a bilayer electron system produced in a wide quantum well

TL;DR

This paper introduces a transparent capacitance measurement method to characterize individual layers in a wide quantum well electron system, enabling determination of electron densities and detection of wave function modifications.

Contribution

The paper presents a novel capacitance-based technique for analyzing and distinguishing layers in a double-layer electron system within a wide quantum well.

Findings

Capacitance measurements reveal electron densities in each layer.

Detection of wave function modifications due to second subband population.

Magnetic field dependence shows quantum Landau level effects.

Abstract

Here we report on a transparent method to characterize individual layers in a double-layer electron system which forms in a wide quantum well and to determine their electron densities. The technique relies on the simultaneous measurement of the capacitances between the electron system and gates located on either side of the well. Modifications to the electron wave function due to the population of the second subband and appearance of an additional electron layer can be detected. The magnetic field dependence of these capacitances is dominated by quantum corrections caused by the occupation of Landau levels in the nearest electron layer. The technique should be equally applicable to other implementations of a double layer electron system.