Electrical Conductivity Mechanisms of the Tm1 – xVxNiSb Semiconductor

The structural, thermodynamic, kinetic, and energy characteristics of the Tm1−xVxNiSb semiconductor are studied over T = 80–400 K and 0 ≤ x ≤ 0.10. The present study demonstrates that the crystal structure of TmNiSb is disordered and contains up to 2% of vacancies at the 4a crystallographic site (Tm atoms), which are gradually filled with V atoms up to x = 0.03 with further V for Tm substitution. The formation of two types of acceptor states with different depths of occurrence is experimentally determined: small acceptors generated by vacancies in the p-TmNiSb structure, and deep ones presumably formed by the vacancies at the Ni 4c site and correspond to the homogeneity region TmxNi1−xSb typical of other RNiSb half-Heusler phases. The results of the DFT modeling, including ground-state energy, distribution of the density of electronic states (DOS), and the band structure of Tm1−xVxNiSb, are consistent with experimental studies.