Fizika Nizkikh Temperatur: Volume 45, Number 2 (February 2019), p. 233-244    ( to contents , go back )

Electronic structure of Pb1–xySnxFeyTe alloys

E.P. Skipetrov, B.B. Kovalev, L.A. Skipetrova, A.V. Knotko, and V.E. Slynko

Lomonosov Moscow State University, 1 Leninskie Gory, Moscow 119991, Russia
E-mail: skip@mig.phys.msu.ru

A.V. Knotko

Lomonosov Moscow State University, 1 Leninskie Gory, Moscow 119991, Russia

V.E. Slynko

I. Frantsevich Institute for Problems of Materials Science NAS str. Wilde, 5, Chernivtsi, 58001, Ukraine

Received October 5, 2018, published online December 20, 2018

Abstract

The phase and elemental composition, galvanomagnetic properties (4.2 ≤ T ≤ 300 К, B ≤ 0.07 T) and Shubnikov–de Haas os-cillations (T = 4.2 К, B ≤ 6.5 T) in Pb1–xySnxFeyTe alloys are studied at a variation of the tin and iron concentration along the single-crystal ingots synthesized by the Bridgman–Stockbarger technique. The microscopic inclusions enriched with iron are found and the distribution of the tin and iron along ingots are determined using the scanning electron microscopy and the x-ray fluorescence microanalysis. An increase in the concentration of holes with increasing concentrations of tin and iron and abnormal temperature dependences of the Hall coefficient, indicating the pinning of the Fermi level by the resonant level of iron are found. To explain the experimental dependences of the hole concentration and Fermi energy relative to the valence band top on the tin content in alloys, a model for the rearrangement of the electronic structure is proposed, assuming the movement of the iron level from the top into the depth of the valence band with an increase in the tin concentration. In the framework of the two-band Kane dispersion law, the compositional coefficient of the iron level movement with respect to the edges of the energy bands with an increase in the tin content in the Pb1–xySnxFeyTe alloys is determined.

Key words: PbTe-based alloys, 3d-transition metal impurities, galvanomagnetic effects, electronic structure, resonant iron level, compositional coefficient of the level motion.

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