We measured the optical conductivity spectra of SrV 10O 15 with V2.8 +, which exhibits an insulating behavior without any phase transition, and compared the results with those of BaV 10O 15, which shows orbital ordering below T c=123 K. We found that a soft gap opens at the lowest temperature but it collapses with increasing temperature in SrV 10O 15, in contrast to a finite charge gap (∼0.3 eV) in BaV 10O 15 below T c. We also found that the difference of the conductivity spectra between SrV 10O 15 and BaV 10O 15 evolves even above T c of Ba, indicating that the fluctuation of orbital ordering produces a pseudogap in BaV 10O 15.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2012 Feb 13|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics