Micro- and nanocrystalline, porous, composite semiconductors

Impurity level of Co in Pb$_{1-x-y}$Sn$_x$Co$_y$Te alloys

E. P. Skipetrov^a, N. S. Konstantinov^a, I. V. Shevchenko^a, E. V. Bogdanov^a, L. A. Skipetrova^a, A. V. Knotko<sup>b

a</sup> Lomonosov Moscow State University, Faculty of Physics, 119991 Moscow, Russia
^b Lomonosov Moscow State University, Faculty of Materials Science, 119991 Moscow, Russia

Abstract: The phase and elemental compositions and galvanomagnetic properties of samples from the Pb$_{1-x-y}$Sn$_x$Co$_y$Te single crystal ingot ($x$ = 0.08, $y$ = 0.01) were studied. The distributions of tin and cobalt impurities along the length of the ingot were determined, and microscopic inclusions of the second phase enriched in cobalt were found at the end of the ingot. An abnormal increase in the Hall coefficient was found with increasing temperature, and in samples from the middle part of the ingot, an increase in the hole concentration and a linear increase in the Fermi energy at $T$ = 4.2 K with increasing tin content were found, indicating pinning of the Fermi level by the resonant Co level located in the valence band. The position of the Co level and the compositional coefficient of its motion relative to the top of the valence band are estimated. A diagram of the rearrangement of the electronic structure of alloys with increasing tin concentration is proposed.

Received: 06.07.2025
Revised: 11.11.2025
Accepted: 11.11.2025

DOI: 10.61011/FTP.2025.08.62191.8347