Two-electron exchange between impurity centers of tin in PbSzSe1–z solid solutions

Resumo

Using emission Mössbauer spectroscopy on ^119mmSn(^119mSn) and ¹¹⁹Sb(¹¹⁹mSn) isotopes, the electron exchange process between neutral and doubly ionized U^– tin centers is studied in partially compensated PbS_zSe_1–z solid solutions. The activation energy of this process for compositions with z ≈ 1 is comparable to the deposition depth of the tin energy levels in the band gap of PbS (~0.11(1) eV, and for compositions with z ≈ 1, it is comparable with the correlation energy of donor U^– tin centers in PbSe (~0.05(1) eV). For all compositions of solid solutions, the exchange is realized by the simultaneous transfer of two electrons with the use of the delocalized states of the valence band.