For authors
Submission status

Archive (English)
      Volume 109
      Volume 108
      Volume 107
      Volume 106
      Volume 105
      Volume 104
      Volume 103
      Volume 102
      Volume 101
      Volume 100
      Volume 99
      Volume 98
      Volume 97
      Volume 96
      Volume 95
      Volume 94
      Volume 93
VOLUME 107 | ISSUE 2 | PAGE 108
Collective infrared excitation in the cage-glass LuB12
By measuring room temperature infrared (40-35000 cm-1) reflectivity of metallic LuB12 single crystals with different isotopic compositions (natB, 10B, 11B), we find that to model the spectrum we had to introduce, additionally to Drude free-carrier component, a broad excitation with unusually large dielectric contribution (\Delta\varepsilon=8000\pm4000) which is characterized by a non-Lorentzian lineshape. It is suggested that the origin of the excitation is connected with cooperative dynamics of Jahn-Teller active B12 molecules producing quasi-local vibrations (rattling modes) of caged lutetium ions. The coupling of the Lu3+ rattling motions with the charge carriers of conduction band is proposed to be the reason of strongly damped character of the excitation.