Apparent critical phenomena in the superionic phase transition of Cu2-xSe
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Date
2016-01-11
Journal Title
Journal ISSN
Volume Title
Publisher
IOP Science
Abstract
The superionic phase transition of Cu2-xSe accompanies drastic changes in transport properties. The Seebeck coefficient increases sharply while the electrical conductivity and thermal diffusivity drops. Such behavior has previously been attributed to critical phenomena under the assumption of a continuous phase transition. However, applying Landau's criteria suggests that the transition should be first order. Using the phase diagram that is consistent with a first order transition, we show that the observed transport properties and heat capacity curves can be accounted for and modeled with good agreement. The apparent critical phenomena is shown to be a result of compositional degree-of-freedom. Understanding of the phase transition allows to explain the enhancement in the thermoelectric figure-of-merit that is accompanied with the transition. © 2016 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
Description
Keywords
Phase transformations, Electric conductivity, Seebeck effect, Phase diagrams, Specific heat, Thermal diffusivity
Citation
Kang, S. D., Danilkin, S. A., Aydemir, U., Avdeev, M., Studer, A. & Snyder, G. J. (2016). Apparent critical phenomena in the superionic phase transition of Cu2-xSe. New Journal of Physics, 18, 013024. doi:10.1088/1367-2630/18/1/013024