DISTINCTIVE FEATURES OF THE MAGNETORESISTANCE OF DEGENERATELY DOPED N-INAS AND THEIR INFLUENCE ON MAGNETIC-FIELD-DEPENDENT MICROWAVE-ABSORPTION

Magnetic-field-dependent microwave absorption and electron spin resona nce are used to investigate magnetoresistive effects in strongly doped n-InAs. It is shown that these effects can be traced back to negative , positive, or oscillatory magnetoresistance (i.e., the Shubnikov-de H aas effect). While the experimental data are in agreement with the pre dictions of theory in the latter two cases, for the negative magnetore sistance there are features that are difficult to interpret, especiall y the absence of any effect at very small fields, much smaller than th e characteristic field H-phi that appears in the theory of quantum cor rections, and the two-dimensionality of bulk samples in fields much la rger than H-phi implied by the observed dependences on temperature and to some extent on the magnetic field. (C) 1998 American Institute of Physics. [S1063-7826(98)01005-9].