Low-Temperature Structure and Dynamics in Cu2Se


SIRUSI A. A. , Ballikaya S. , Uher C., ROSS J. H.

JOURNAL OF PHYSICAL CHEMISTRY C, vol.119, no.35, pp.20293-20298, 2015 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 119 Issue: 35
  • Publication Date: 2015
  • Doi Number: 10.1021/acs.jpcc.5b06079
  • Title of Journal : JOURNAL OF PHYSICAL CHEMISTRY C
  • Page Numbers: pp.20293-20298

Abstract

We report Cu-63 and Cu-65 NMR on Cu2Se, a superionic conductor of interest for thermoelectric and other applications. Results demonstrate an initial appearance of ionic hopping in a narrow temperature range above 100 K, coinciding with the recently observed low-temperature phase transition. At room temperature and above, this goes over to rapid Cu-ion hopping and a single motionally narrowed line both above and below the alpha-beta structural transition. The low-temperature alpha' phase exhibits a sizable metallic shift, in contrast to the high-temperature structures. The large variation in native carrier density, significantly enhanced at positions associated with Cu vacancies, indicates the strong influence of an impurity band on low-temperature electronic transport.