Magnetoresistance of an Anderson Insulator of Bosons

Anirban Gangopadhyay, Victor Galitski, and Markus Müller

Phys. Rev. Lett. 111, 026801 – Published 9 July 2013

Abstract

We study the magnetoresistance of two-dimensional bosonic Anderson insulators. We describe the change in spatial decay of localized excitations in response to a magnetic field, which is given by an interference sum over alternative tunneling trajectories. The excitations become more localized with increasing field (in sharp contrast to generic fermionic excitations which get weakly delocalized): the localization length $ξ (B)$ is found to change as $ξ^{- 1} (B) - ξ^{- 1} (0) \sim B^{4 / 5}$ . The quantum interference problem maps onto the classical statistical mechanics of directed polymers in random media (DPRM). We explain the observed scaling using a simplified droplet model which incorporates the nontrivial DPRM exponents. Our results have implications for a variety of experiments on magnetic-field-tuned superconductor-to-insulator transitions observed in disordered films, granular superconductors, and Josephson junction arrays, as well as for cold atoms in artificial gauge fields.

Received 1 November 2012

DOI:https://doi.org/10.1103/PhysRevLett.111.026801

Authors & Affiliations

Anirban Gangopadhyay¹, Victor Galitski^1,2, and Markus Müller^3,4

¹Department of Physics, Center for Nanophysics and Advanced Materials, University of Maryland, College Park, Maryland 20742-4111, USA
²Department of Physics, Joint Quantum Institute, University of Maryland, College Park, Maryland 20742-4111, USA
³The Abdus Salam International Centre for Theoretical Physics, P.O. Box 586, 34151 Trieste, Italy
⁴Kavli Institute for Theoretical Physics, University of California Santa Barbara, California 93106-4030, USA