Low Temperature Physics: 31, 285 (2005); https://doi.org/10.1063/1.1884432 (5 pages)
Физика Низких Температур: Том 31, Выпуск 3-4 (Март 2005), c. 377-381    ( к оглавлению , назад )

Level statistics for quantum Hall systems

V. Kagalovsky

Negev Academic College of Engineering, Beer-Sheva 84100, Israel
E-mail: victork@nace.ac.il

B. Horovitz, and Y. Avishai

Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel

Received July 12, 2004


Level statistics for two classes of disordered systems at criticality are analyzed in terms of different realizations of the Chalker–Coddington network model. These include: 1) Re-examination of the standard U(1) model describing dynamics of electrons on the lowest Landau level in the quantum Hall effect, where it is shown that after proper local unfolding the nearest-neighbor spacing distribution (NNSD) at the critical energy follows the Wigner surmise for Gaussian unitary ensembles (GUE). 2) Quasi-particles in disordered superconductors with broken time reversal and spin rotation invariance (in the language of random matrix theory this system is a representative of symmetry class D in the classification scheme of Altland and Zirnbauer). Here again the NNSD obeys the Wigner surmise for 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.

73.20.Fz - Weak or Anderson localization
72.15.Rn - Localization effects (Anderson or weak localization)