Low-Temperature Structure and Dynamics in Cu2Se

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

JOURNAL OF PHYSICAL CHEMISTRY C, cilt.119, sa.35, ss.20293-20298, 2015 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 119 Sayı: 35
  • Basım Tarihi: 2015
  • Doi Numarası: 10.1021/acs.jpcc.5b06079
  • Dergi Adı: JOURNAL OF PHYSICAL CHEMISTRY C
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.20293-20298
  • İstanbul Üniversitesi Adresli: Evet

Özet

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.