Apparent critical phenomena in the superionic phase transition of Cu2-xSe

Stephen Dongmin Kang, Sergey A. Danilkin, Umut Aydemir, Maxim Avdeev, Andrew Studer, G. Jeffrey Snyder

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


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 Landaus 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.

Original languageEnglish (US)
Article number013024
JournalNew Journal of Physics
Issue number1
StatePublished - Jan 1 2016


  • phase transition
  • superioinic conductors
  • thermoelectrics
  • thermopower

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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