Europhys. Lett, 47 (2), pp. 240-246 (1999)
Localization of fermions in an anisotropic random magnetic field
Department of Physics, The Pennsylvania State University
University Park, PA 16802, USA
Institute for Theoretical Physics, University of California
Santa Barbara, CA 93106, USA
(received 16 April 1999; accepted 25 May 1999)
PACS. 72.10Bg - General formulation of transport
PACS. 72.15Rn - Localization effects (Anderson or weak localization).
PACS. 71.55Jv - Disordered structures; amorphous and glassy solids.
We study the localization of fermions in an anisotropic random magnetic field in two dimensions. It is assumed that the randomness in a particular direction is stronger than those in the other directions. We consider a network model of zero-field contours, where there are two types of randomness --the random tunneling matrix element at the saddle points and the unidirectional random variation of the number of fermionic states following zero-field contours. After averaging over the random complex tunneling amplitude, the problem is mapped to an SU(2N) random exchange quantum spin chain in the limit. We suggest that the fermionic state becomes critical in an anisotropic fashion.
Copyright EDP Sciences