On the tensoresistance of $n$-Ge and $n$-Si crystals with radiation-induced defects

A variation in the tensoresistance of $n$-Ge:Sb and $n$-Si:As crystals as a result of irradiation with $\gamma$-ray photons ($^{60}$Co source) at fixed temperatures under conditions of the application of uniaxial elastic stress (0 $\le X\le$ 1.2 GPa) along the main crystallographic direction is studied. It is found that, in the case of the deformation axis being in an asymmetric position relative to the isoenergetic ellipsoids, there is a maximum for the dependences of the tensoresistance $\rho_X/\rho_0 = f (X)$; an explanation as to the nature of the observed effect is suggested. Tensoresistance is revealed in unirradiated $n$-Si:As crystals in the case of the deformation axis being in a symmetric position relative to all isoenergetic ellipsoids; the value of the tensoresistance as a result of irradiation with $\gamma$-ray photons decreases. It is shown that this effect can be attributed to a variation in the mobility of electrons in the conduction band as a result of an increase in the transverse effective mass and the appearance of new deep-level centers under the effect of irradiation, respectively.