LIQUATION PHENOMENA IN CMT MELTS AND STRUCTURAL FEATURES IN CADMIUM AND MERCURY TELLURIDES IN A LIQUID-PHASE

The temperature dependence of CdxHg1-xTe melt density of Various compo sitions in the range upto 20 mol% CdTe has been investigated by the ga mma-ray attenuation method. Both the density gradient and the concentr ation gradient, stable in time, have been found by density measurement s along the sample height. This gradient can be regarded as a new phys ical phenomenon in cadmium-mercury-tellurium melts (CMT). The concentr ation and density gradient is related to the peculiarities of intermol ecular interaction nature. Success in an associated model approximatio n was achieved at the expense of introduction of Kg(2)Te(3) associates into the molecular composition of CMT melts. As for the liquation phe nomena mentioned above, they might occur at the expense of interaction between Hg2Te3 and CdTe associates forming [Cd2+(Hg2Te4)(2-)] complex es. The atomic structure of cadmium and mercury tellurides has been an alyzed by molecular dynamics methods. Structural characteristics of ca dmium and mercury telluride melts in the vicinity of the compound melt ing point have been examined using potentials of the Stillinger and We ber type. The agreement between the experimental and calculated struct ure factors of molten HgTe and CdTe is satisfactory. Analysis of the b ond-angle distributions of atoms indicates that in 1-CdTe a covalent b onding network predominant with tetrahedral coordination takes place, while 1-HgTe possesses an inhomogeneous structure. (C) 1998 Published by Elsevier Science B.V. All rights reserved.