Activated Transport in the individual Layers that form the $\nu_T$=1 Exciton Condensate

TL;DR

This paper investigates thermally activated transport in a bilayer quantum Hall system at total filling factor 1, revealing layer-specific activation energies and asymmetries related to charge excitations.

Contribution

It provides new insights into layer-specific activation energies and asymmetries in a bilayer quantum Hall system at $ u_T=1$, especially under imbalance conditions.

Findings

Activation energy increases as $d/\ell_B$ decreases below 1.65.

Activated transport occurs in each layer separately under imbalance.

Asymmetry in activation energies indicates different charge-excitation gaps for positive and negative imbalance.

Abstract

We observe the total filling factor $\nu_{T}$=1 quantum Hall state in a bilayer two-dimensional electron system with virtually no tunnelling. We find thermally activated transport in the balanced system with a monotonic increase of the activation energy with decreasing $d/\ell_B$ below 1.65. In the imbalanced system we find activated transport in each of the layers separately, yet the activation energies show a striking asymmetry around the balance point. This implies that the gap to charge-excitations in the {\em individual} layers is substantially different for positive and negative imbalance.