Infrared absorption study of Ca2- xNaxCuO 2X2 (X=Cl, Br)

Takumi Hasegawa, Norio Ogita, Toshihisa Kondo, Yuji Zenitani, Hirokazu Kawashima, Teruhiko Suzuki, Jun Akimitsu, Masayuki Udagawa

Research output: Chapter in Book/Report/Conference proceedingConference contribution


IR-active phonon spectra of Ca2- xNaxCuO 2X2 (X=Cl, Br) have been measured by a CsI powder method in the energy region between 250 and 4000 cm-1 at room temperature. Two absorption peaks with the Eu symmetry have been clearly observed for the undoped crystals of Ca2CuO2Cl2 and Ca2CuO2Br2. However, the observed two peaks disappear for the Na-doped superconducting samples. From the comparison of the highest-energy Eu phonon, which is the Cu-O stretching vibration, the interaction of the Cu-O bond along the CuO2 plane for the T-structure is stronger by 20 % than that of the T′-structure in the 2-1-4 family. To understand the effect of the apical ions, first-principles calculations of the Eu phonon energy for T- and T′-structure La2CuO4 is performed and the preliminary results agree with the experimental tendency.

Original languageEnglish
Title of host publicationLOW TEMPERATURE PHYSICS
Subtitle of host publication24th International Conference on Low Temperature Physics - LT24
Number of pages2
Publication statusPublished - Dec 1 2006
Externally publishedYes
EventLOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24 - Orlando, FL, United States
Duration: Aug 10 2006Oct 17 2006

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


OtherLOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24
Country/TerritoryUnited States
CityOrlando, FL


  • Carrier doping
  • Infrared absorption
  • Phonon
  • Superconductivity

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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