Pseudospin Soliton in the $\nu=1$ Bilayer Quantum Hall State

TL;DR

This paper studies the formation and behavior of pseudospin soliton lattices in a bilayer quantum Hall system at filling factor one, revealing anisotropic magnetoresistance peaks and phase transitions influenced by magnetic field and density imbalance.

Contribution

It introduces the observation of pseudospin soliton lattice formation and characterizes its properties and phase diagram in the bilayer quantum Hall state at bc=1.

Findings

Anisotropic magnetoresistance peak at phase transition.

Temperature-dependent dissipation linked to pseudospin solitons.

Phase diagram showing dependence on magnetic field and electron density.

Abstract

We investigate a domain structure of pseudospins, a soliton lattice in the bilayer quantum Hall state at total Landau level filling factor $\nu =1$, in a tilted magnetic field, where the pseudospin represents the layer degree of freedom. An anomalous peak in the magnetoresistance $R_{xx}$ appears at the transition point between the commensurate and incommensurate phases. The $R_{xx}$ at the peak is highly anisotropic for the angle between the in-plain magnetic field $B_\parallel $ and the current, and indicates a formation of the soliton lattice aligned parallel to $B_\parallel $. Temperature dependence of the $R_{xx}$ peak reveals that the dissipation is caused by thermal fluctuations of pseudospin solitons. We construct a phase diagram of the bilayer $\nu =1$ system as a function of $B_\parallel$ and the total electron density. We also study effects of density imbalance between the two layers.