Pseudospin Soliton in theν=1Bilayer Quantum Hall State

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 Rxx appears at the transition point between the commensurate and incommensurate phases. The Rxx 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. The temperature dependence of the Rxx peak reveals that the dissipation is caused by thermal fluctuations of pseudospin solitons. We also study a phase diagram of the bilayer nu = 1 system, and the effects of density imbalance between the two layers.

Bilayer quantum Hall system atνt=1: Pseudospin models and in-plane magnetic field

“…The parameter values reported in Ref. 8 give a ͉lQ c ͉ of about 2.1-2.2. This value invalidates the assumption that ͉lQ͉ Ӷ 1, which was made to derive the Pokrovsky-Talapov model.…”

“…8 Working at a temperature T = 130 mK, measuring on a sample with d = 23 nm and t = ⌬ SAS / 2 = 5.5 K, the ͑red͒ dots in Fig. 2 were obtained.…”

“…In order to compare the theory to the experimental findings presented in Ref. 8, we need to express the total electron density n T as a function of the critical in-plane field. The total electron density is related to B Ќ by…”

“…5 In addition to the compressible-incompressible transition discussed above, a commensurate-incommensurate transition has been identified, driven by an in-plane magnetic field. 6,7 Recently, detailed measurements on this aspect of the system 8 …”

Activation study of collective excitations of the soliton-lattice phase in theν=1double-layer quantum Hall state

“…Recent experiment in the double-layer = 1 QH state indicates the existence of pseudospin solitons by the observation of the anisotropic conductivity for the angle between B ʈ and detective current I. 16 In this Brief Report, we investigate the collective excitation modes of the SL in the IC phase by detailed activation energy gap measurements under tilted magnetic fields. As a double-quantum-well sample is tilted in a magnetic field, the activation energy gap of the double-layer = 1 QH state drops rapidly in the C phase and takes a minimum near the C-IC phase transition point.…”