[15p-P4-1~15] 6.6 Probe Microscopy

[15p-P4-3] Selective STM light emission from metallic phase of VO₂

〇Joe Sakai¹, Masashi Kuwahara², Masaki Hotsuki³, Satoshi Katano³, Yoichi Uehara³ (1.GREMAN, Univ. Tours, 2.AIST, 3.RIEC, Tohoku Univ.)

Keywords:STM light emission, VO2, interband transition

We observed scanning tunneling microscope light emission (STM-LE) induced by a tunneling current at the gap between an Ag tip and a VO₂ thin film that consisted of both semiconducting M-phase and metallic R-phase, as well as the scanning tunneling spectroscopy (STS) profiles. We found that STM-LE with certain photon energies of 2.0 eV and/or 2.7 eV occurs selectively from R-phase domains of VO₂, while no STM-LE was observed from M-phase. The bias dependency of the light emission spectra and the calculation of spectra have enabled us to conclude that the mechanism of STM-LE from R-phase VO₂ is an interband transition process.