Defect structure of Sb2-xCrxTe3 single crystals.

Single crystals of Sb₂Te₃ doped with Cr (c_Cr=0–6×10²⁰ cm^-3) were prepared by the Bridgman method. The measurements of the Hall coefficient reveal a nonmonotonous dependence of hole concentrations on the Cr content in the crystal. The hole concentration decreases at low content of Cr, while at higher content of Cr it increases again. However, according to magnetic measurements, Cr atoms enter the structure and form uncharged substitutional defects Cr_Sb^×, which cannot affect the free carrier concentration directly. The observed dependence can be elucidated by means of a point defect model. The model is based on an assumption that defect structure of Sb₂Te₃ can be treated as hybrid Schottky and antisite defect disorder. Thus, we assume an interaction of Cr_Sb^× with the most populated native defects in the structure—antisite defects Sb_Te^-1 and vacancies in the Te sublattice V_Te⁺². [ABSTRACT FROM AUTHOR]