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

[15p-P4-4] Pump-Probe STM light emission spectroscopy of VO₂

Joe Sakai¹, Satoshi Katano², Masashi Kuwahara³, 〇Yoichi Uehara² (1.GREMAN, Tours Univ., 2.RIEC, Tohoku Univ., 3.AIST)

Keywords:Time resolved STM light emission, VO2

The sample is a 34 nm-thick VO₂ film grown on a rutile TiO₂ (001) substrate consisted of both rutile (R)- and monoclinic (M)- structure phases of a few 10 nm-sized domains at room temperature. STM light emission is detected only when the tip is fixed over a R-phase domain. In this investigation, the STM tip was fixed over a R-phase domain, and STM light emission was observed as a function of delay time T between the pump and probe ps laser pulses with which the tip-sample gap is irradaiated. STM light emission spectra characteristic for the M-phase was observed for T = 20~50 ps, showing that the phase transition from R to M phase is induced at 20 ps after irradiation of the pump pulse and is maintained for 30 ps.