Galvanomagnetic properties and electronic structure of iron-doped PbTeстатья
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Дата последнего поиска статьи во внешних источниках: 22 февраля 2016 г.
Аннотация:We synthesize an iron-doped PbTe single-crystal ingot and investigate the phase composition and the distribution of the iron impurity along the ingot as well as galvanomagnetic properties in weak magnetic fields (4.2 K≤T≤300 K, B≤0.07 T) of Pb1-yFeyTe alloys. We find microscopic inclusions enriched with iron and regions with a chemical composition close to FeTe in the heavily-doped samples, while the iron impurity content in the main phase rises only slightly along the length of the ingot reaching the impurity solubility limit at approximately 0.6 mol. %. Samples from the initial and the middle parts of the ingot are characterized by the p-type metal conductivity. An increase of the iron impurity content leads to a decrease in the free hole concentration and to a stabilization of galvanomagnetic parameters due to the pinning of the Fermi level by the iron resonant impurity level EFe lying under the bottom of the valence band (Ev–EFe=16 meV). In the samples from the end of the ingot a p-n inversion of the conductivity type and an increase of the free electron concentration along the ingot are revealed despite the impurity solubility limit being reached. The kinetics of changes of charge carrier concentration and of the Fermi energy along the ingot is analyzed in the framework of the six-band Dimmock dispersion relation. A model is proposed for the electronic structure rearrangement of Pb1-yFeyTe with doping, which also may be used for PbTe doped with other transition metals.