Superfluidity and effective mass of magnetoexcitons in topological insulator bilayers: Effect of inter-Landau-level Coulomb interaction

¹ LCP, Institute of Applied Physics and Computational Mathematics - P.O. Box 8009, Beijing 100088, PRC
² State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences - P. O. Box 912, Beijing 100083, PRC

^a zhang_ping@iapcm.ac.cn

Received: 29 February 2012
Accepted: 19 April 2012

Abstract

The effective mass and superfluidity-normal phase transition temperature of magnetoexcitons in topological insulator bilayers are theoretically investigated. The intra-Landau-level Coulomb interaction is treated perturbatively, from which the effective magnetoexciton mass is analytically discussed. The inclusion of inter-Landau-level Coulomb interaction by more exact numerical diagonalization of the Hamiltonian brings out important modifications to magnetoexciton properties, which are specially characterized by prominent reduction in the magnetoexciton effective mass and promotion in the superfluidity-normal phase transition temperature at a wide range of external parameters.