Correlation between p-type conductivity and electronic structure of Cr-deficient CuCr 1-x O 2 (x = 0 - 0.1)

Shashi B. Singh, L. T. Yang, Y. F. Wang, Y. C. Shao, C. W. Chiang, J. W. Chiou, K. T. Lin, S. C. Chen, Bo-Yao Wang, C. H. Chuang, D. C. Ling, W. F. Pong, M. H. Tsai, H. M. Tsai, C. W. Pao, H. W. Shiu, C. H. Chen, H. J. Lin, J. F. Lee, H. YamaneN. Kosugi

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The correlation between the p-type hole conduction and the electronic structures of Cr-deficient CuCr 1-x O 2 (x=0-0.1) compounds was investigated using O K-, Cu, and Cr L 3,2 -edge x-ray absorption near-edge structure (XANES), scanning photoelectron microscopy, and x-ray emission spectroscopy measurements. XANES spectra reveal a gradual increase in the Cu valence from Cu1 + to Cu2 + with increasing Cr deficiency x, whereas, the valence of Cr remains constant as Cr3 + . These results indicate that the p-type conductivity in the CuCr 1-x O 2 samples is enhanced by a Cu1 + -O-Cu2 + rather than a Cr3 + -Cr4 + or direct Cu1 + -Cu2 + hole mechanism. Remarkable Cr-deficiency-induced changes in the densities of Cu 3d, Cu 3d-O 2p, and O 2p states at or near the valence-band maximum or the Fermi level were also observed. In addition, a crossover of conduction mechanism from thermally activated (TA) hopping to a combination of TA and Mott's three-dimensional variable range hopping occurs around 250 K.

Original languageEnglish
Article number241103
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number24
DOIs
Publication statusPublished - 2012 Dec 7

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this