HAIT Journal of Science and Engineering
Volume 1, Issue 3, pp. 542-553
© 2004 Holon Academic Institute of Technology


Thermal quantum Hall effect in disordered superconductors

Victor Kagalovsky1,*, Baruch Horovitz2, and Yshai Avishai2

1Negev Academic College of Engineering, Beer-Sheva 84100, Israel
2Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
*Corresponding author: victork@nace.ac.il
Received 24 October 2004, accepted 30 November 2004


We study the symmetry class for localization which arises from models of noninteracting quasiparticles in disordered superconductors that have neither time-reversal nor spin-rotation invariance. Two-dimensional systems in this category, which is known as class D, can display phases with three different types of quasiparticle dynamics: metallic, localized, or with a quantized (thermal) Hall conductance. Correspondingly, they can show a variety of delocalization transitions. We illustrate this behavior by investigating numerically the phase diagrams of network models with the appropriate symmetry and show the appearance of the metallic phase. We also study level statistics for this symmetry class and find that the nearest neighbor spacing distribution (NNSD) at the critical energy follows the Wigner's surmise for Gaussian Unitary Ensembles (GUE) , reflecting therefore only "basic" discrete symmetries of the system (time reversal violation) and ignoring particle-hole symmetries and other finer details (criticality). In the localized regime level repulsion is suppressed.

PACS: 73.20.Fz, 72.15.Rn


Presented at International Workshop Correlated Electrons at High Magnetic Fields. Ein-Gedi/Holon, Israel, 19-23 December 2004

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