Electronic Structure of VO_2 near Phase Transition by Tunneling Spectroscopy

摘要

Tunneling spectroscopy was carried out on W doped VO_2 single crystal in the temperature region across the phase transition. Double pseudo gap structures were observed across the Fermi level at temperatures below the phase transition. When the temperature was increased across the phase transition, the outer gap structure disappeared and the inner gap structure of about 0.36 eV became sharp. A precursor of phase transition to low temperature phase was observed in the tunneling density of states near the Fermi level, when the temperature approached 0.2 K to the threshold of transition in the electrical resistivity.