Numerical calculations for large positive magnetoresistance ratios R(B)/R(0) in insulating materials

Citation
R. Rosenbaum et al., Numerical calculations for large positive magnetoresistance ratios R(B)/R(0) in insulating materials, PHYSICA B, 294, 2001, pp. 486-488
Citations number
6
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
PHYSICA B
ISSN journal
09214526 → ACNP
Volume
294
Year of publication
2001
Pages
486 - 488
Database
ISI
SICI code
0921-4526(200101)294:<486:NCFLPM>2.0.ZU;2-1
Abstract
Numerical calculations are presented for predicting the large positive magn etoresistance ratios R(B)/R(O) which are often observed in insulating mater ials. The magnetic field causes shrinkage of the localized electronic wave function, resulting in less overlapping between the hopping sites and hence a relatively large increase of the resistance in the insulating material. Two specific cases are considered: (a) an insulating 3D sample that exhibit s a "Mott" variable-range hopping law in its zero-field resistance and (b) an insulating 3D sample that exhibits an "Efros-Shklovskii'' variable-range hopping law in its zero field resistance. The numerical calculations are t abulated. The general 3D "soft gap" case is also discussed. (C) 2001 Elsevi er Science B.V. All rights reserved.