Effective pseudospin wave model for the coherent stripe phase in a bilayer system

Abstract

Hartree–Fock theory predicts a stripe-like ground state for the two-dimensional electron gas in a bilayer quantum Hall system in a quantizing magnetic field at filling factor 4 N + 1 (with N > 0 ). This stripe state contains quasi-1D linear coherent regions where electrons are delocalized across both wells and which support low-energy collective excitations in the form of phonons and pseudospin waves. We have recently computed the dispersion relation of these low-energy modes in the generalized random phase approximation. In this work, we propose an effective pseudospin model in which the stripe state is modeled as an array of coupled 1D anisotropic X– Y systems. The coupling constants and stiffness of our model are extracted from the density and pseudospin response functions computed in the GRPA.