Spin Bose-glass phase in bilayer quantum Hall systems at nu=2

Abstract

We develop an effective spin theory to describe magnetic properties of the n 2 quantum Hall bilayer systems. In the absence of disorder this theory agrees with the microscopic Hartree-Fock calculations, and for finite disorder it predicts the existence of a novel spin Bose-glass phase. The Bose glass is characterized by the presence of domains of canted antiferromagnetic phase with zero average antiferromagnetic order and short range correlations. It has infinite antiferromagnetic transverse susceptibility and finite longitudinal spin susceptibility. Transition from the canted antiferromagnetic phase to the spin Bose-glass phase is characterized by a universal value of the spin conductance.