Features of an intermetallic n-ZrNiSn semiconductor heavily doped with atoms of rare-earth metals

The crystal structure, density of electron states, electron transport, and magnetic characteristics of an intermetallic n-ZrNiSn semiconductor heavily doped with atoms of rare-earth metals (R) have been studied in the ranges of temperatures 1.5-400 K, concentrations of rare-earth metal 9.5 x 1019-9.5 x 1021 cm-3, and magnetic fields H ≤ 15 T. The regions of existence of Zr1-xRxNiSn solid solutions are determined, criteria for solubility of atoms of rare-earth metals in ZrNiSn and for the insulator-metal transition are formulated, and the nature of 'a priori doping' of ZrNiSn is determined as a result of redistribution of Zr and Ni atoms at the crystallographic sites of Zr. Correlation between the concentration of the R impurity, the amplitude of modulation of the bands of continuous energies, and the degree of occupation of potential wells of small-scale fluctuations with charge carriers is established. The results are discussed in the context of the Shklovskii-Efros model of a heavily doped and compensated semiconductor.