Quasi-Particle Localization by Disorder in ν = 5/2 Fractional Quantum Hall State and Its Potential Application

P. Goswami Deshbandhu College, University of Delhi, Kalkaji, New Delhi-110019, India

Received: December 28, 2011; in final form: June 20, 2012

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We consider the filling factor 5/2 fractional quantum Hall state of spin-polarized fermions in a dirty (mobility μb<10 m2 V-1 s-1) bi-layer quantum well system.We show that the system undergoes a quantum phase transition from the effective two-component state to an effective single-component state, at fixed charge imbalance regulatory parameter Δc and constant layer separation, as the inter-layer tunneling strength ΔSAS is increased. At finite and constant ΔSAS, a transition from the latter state to the former state is also possible upon increasing the parameter Δc. We identify the order parameter to describe quantum phase transition as a pseudo-spin component and calculate this with the aid of the Matsubara propagators in the finite-temperature formalism. Our treatment is able to show that, at low temperature(<0.1 K) and low value of charge imbalance regulatory parameter, there is a competition between the disorder and the inter-layer tunneling strength in the sample. The competition leads to the quasi-particle localization at low tunneling strength.

DOI: 10.12693/APhysPolA.122.741 PACS numbers: 73.21.Fg