Features of conduction mechanisms in $n$-HfNiSn semiconductor heavily doped with a Rh acceptor impurity

The crystal structure and electron-density distribution, as well as the energy, kinetic, and magnetic characteristics of $n$-HfNiSn intermetallic semiconductor heavily doped with a Rh acceptor impurity in the temperature range $T$ = 80–400 K, in the acceptor-concentration range $N_A^{\mathrm{Rh}}\approx$ 9.5 $\times$ 10$^{19}$ – 1.9 $\times$ 10$^{21}$ cm$^{-3}$ ($x$ = 0.005–0.10), and in magnetic fields $H\le$ 10 kG are investigated. It is established that doping is accompanied by a simultaneous decrease in concentration, the elimination of donor-type structural defects (to $x\approx$ 0.02), and an increase in the concentration of acceptor-type structural defects (0 $<x\le$ 0.10). The dependence of the degree of semiconductor compensation on temperature is revealed. A model of the spatial arrangement of atoms in HfNi$_{1-x}$Rh$_x$Sn is proposed, and the results of calculating the electron structure based on this model agree with the results of investigations of the kinetic and magnetic characteristics of the semiconductor. The results are discussed within the context of the Shklovskii–Efros model for a heavily doped and compensated semiconductor.