Enhanced room-temperature geometric magnetoresistance in inhomogeneous narrow-gap semiconductors

A symmetric van der Pauw disk of homogeneous nonmagnetic indium antimonide with an embedded concentric gold inhomogeneity is found to exhibit room-tem perature geometric magnetoresistance as high as 100, 9100, and 750,000 perc ent at magnetic fields of 0.05, 0.25, and 4.0 teslas, respectively. For inh omogeneities of sufficiently Large diameter relative to that of the surroun ding disk, the resistance is field-independent up to an onset field above w hich it increases rapidly. These results can be understood in terms of the field-dependent deflection of current around the inhomogeneity.