Magnetic field induced Coulomb blockade in small disordered delta-doped heterostructures

TL;DR

This paper predicts that in small disordered delta-doped heterostructures, resistance oscillations occur at low temperatures due to electron droplet formation, which are significantly amplified by magnetic fields, and relate to phenomena like Coulomb blockade.

Contribution

It introduces a model explaining resistance oscillations in low-density 2D electron gases, emphasizing the role of magnetic fields and sample size, connecting to experimental observations of Coulomb blockade effects.

Findings

Resistance oscillations are intrinsic to small samples at low temperatures.

Magnetic fields greatly enhance these resistance oscillations.

Larger samples exhibit variable range hopping resistivity.

Abstract

At low densities, electrons confined to two dimensions in a delta-doped heterostructure can arrange themselves into self-consistent droplets due to disorder and screening effects. We use this observation to show that at low temperatures, there should be resistance oscillations in low density two dimensional electron gases as a function of the gate voltage, that are greatly enhanced in a magnetic field. These oscillations are intrinsic to small samples and give way to variable range hopping resistivity at low temperatures in larger samples. We place our analysis in the context of recent experiments where similar physical effects have been discussed from the point of view of a Wigner crystal or charge density wave picture.