On the diffusivityhyphen;mobility ratio in smallhyphen;gap semiconductors in the presence of a strong magnetic field: Theory and suggestion for experimental determination

摘要

An attempt is made to study the Einstein relation for the diffusivityhyphen;mobility ratio of the electrons in degeneratenhyphen;type smallhyphen;gap semiconductors under strong magnetic field on the basis of threehyphen;band Kane model without any approximations of band parameters and incorporating the electron spin and broadening of Landau levels, respectively. It is found, takingnhyphen;Hg1minus;xCdxTe as an example, that the Einstein relation exhibits an oscillatory magnetic field dependence due to Shubnikovndash;de Haas effect and decreases with increasing alloy composition. Besides the same ratio increases with increasing electron concentration and is in close agreement with the suggested experimental method of determining the Einstein relation in degenerate semiconductors having arbitrary dispersion laws. In addition, the corresponding wellhyphen;known results of parabolic semiconductors both in the presence and absence of magnetic field have been obtained from the generalized expressions under certain limiting conditions.