Effect of fluctuations on electron and phonon processes and thermodynamic parameters of Ag{sub 2}Te and Ag{sub 2}Se in the region of phase transition
Temperature dependences of electrical conductivity {sigma}, thermoelectric power {alpha}, results of differential thermal analysis {delta}T{sub y}, thermal conductivity {chi}, temperature conductivity {kappa}, and heat capacity C{sub p} were studied in Ag{sub 2}Te and Ag{sub 2}Se semiconductors in the region of the phase transition. Two extrema are observed in the temperature dependence {chi}(T): a maximum in the region of the {alpha}' {sup {yields}} {beta}' transition and a minimum in the region of the {beta}' {sup {yields}} {beta} transition; these extrema are caused by the similar dependence C{sub p}(T). It is shown that the {alpha} {sup {yields}} {alpha}' and {beta}' {sup {yields}} {beta} transitions are displacement transitions, while the {alpha}' {sup {yields}} {beta}' transition is of reconstruction type. It is established that the disorder parameter {eta} in silver chalcogenides is highly smeared in the region of the phase transition; therefore, disordering of phases at the point of the phase transition is incomplete: 73, 62, and 48% in Ag{sub 2}Te, Ag{sub 2}Se, and Ag{sub 2}S, respectively. The minimum volumes V{sub ph} for new phases are calculated; it is shown that the value of V{sub ph} in displacement transitions is larger than in the reconstruction-type transitions.
- OSTI ID:
- 21087894
- Journal Information:
- Semiconductors, Vol. 42, Issue 4; Other Information: DOI: 10.1134/S1063782608040052; Copyright (c) 2008 Pleiades Publishing, Ltd; Country of input: International Atomic Energy Agency (IAEA); ISSN 1063-7826
- Country of Publication:
- United States
- Language:
- English
Similar Records
Energy spectrum of charge carriers in Ag{sub 2}Te
Ag2Se to KAg3Se2: Suppressing Order–Disorder Transitions via Reduced Dimensionality