[2Bp01-10] Surface Analysis/Applied Surface Science/Evaluation Technique (ASS)

[2Bp02] Exciton formation in a single molecule triggered by field-driven ultrafast electron tunneling

*Kensuke Kimura¹, Hiroshi Imada¹, Ikufumi Katayama², Jun Takeda², Yousoo Kim¹ (1. RIKEN, 2. Department of Physics, Yokohama National University)

The combination of a single-cycle THz pulse and a scanning tunneling microscope (STM) paves the way to investigate ultrafast dynamics with the nanometer and picosecond resolutions. In THz-STM, the tunneling barrier of STM junction is modulated by the oscillation of THz electric field. Due to the limitation of bandwidth of electrical circuit, conventional THz-STM only measures “time-averaged” or “net” field-driven tunneling current, thus it is difficult to determine how electrons are manipulated by positive and negative components within a single-cycle electric field oscillation. In our group, we have combined a photon detection system with a THz-STM for investigating excitation and energy dissipation processes triggered by THz-field-driven tunneling. In this work, we revealed field-driven ultrafast charge transfer between the STM tip and a molecule by measuring luminescence signal from the molecule.