Coulomb and tunneling coupled trilayer systems at zero magnetic field

TL;DR

This paper investigates the ground-state electronic configurations of Coulomb and tunneling coupled trilayer systems at zero magnetic field using a variational Hartree-Fock approach, revealing the interplay between tunneling, electrostatic, and exchange energies.

Contribution

It provides a detailed analysis of how tunneling and electrostatic interactions influence the ground state in trilayer systems, highlighting the transition between different physical regimes.

Findings

Tunneling dominates at small layer separations.

Electrostatic Hartree energy dominates at large layer separations.

Inter-layer exchange stabilizes a balanced, equally occupied layer configuration.

Abstract

The ground-state electronic configuration of three coupled bidimensional electron gases has been determined using a variational Hartree-Fock approach, at zero magnetic field. The layers are Coulomb coupled, and tunneling is present between neighboring layers. In the limit of small separation between layers, the tunneling becomes the dominant energy contribution, while for large distance between layers the physics is driven by the Hartree electrostatic energy. Transition from tunneling to hartree dominated physics is shifted towards larger layer separation values as the total bidimensional density of the trilayers decreases. The inter-layer exchange helps in stabilize a "balanced" configuration, where the three layers are approximately equally occupied; most of the experiments are performed in the vicinity of this balanced configuration. Several ground-state configurations are consequence of a delicate interplay between tunneling and inter-subband exchange.