Phase transitions in copper tellurides

This paper presents the results of model calculations structure Cu-Te system at low temperatures, as well a study and phase transitions synthesized non-stoichiometric compounds copper tellurides. For first time, using USPEX evolutionary algorithm, computer search for stable phases tellurides Cu n Te m (n,m = 1÷10) were carried out. At temperature T 0 K pressure p 1 atm. As structures, compositions 5 4 , 3 2 7 identified, which are indicated in triclinic monoclinic syngonies. Based on diagram, calorimetric measurements X-ray diffraction studies experimentally samples telluride, it was found that 1.96 Te, 1.85 1.80 1.75 room single-phase. The described by hexagonal crystalline superstructures obtained basis Novotny with different degrees unit cell parameter multiplicity. Cu1.96Te is an orthorhombic lattice parameters also multiples phase. high all 2−x (x=0.04, 0.15, 0.20, 0.25) transform into high-temperature disordered FCC structures exist up to their melting point. It shown these transition low-temperature occurs through series polymorphic transformations.