[1A04-09] Probe Microscopy 

2:15 PM - 2:45 PM JST(5:15 AM - 5:45 AM UTC)

[1A05【依頼講演】] Atomic-scale manipulation of single impurity quantum states in narrow-gap semiconductor InAs using scanning tunneling microscope

*Kiyoshi Kanisawa¹ (1. NTT Basic Research Laboratories (Japan))

The formation of metastable donor complexes (DX centers) is studied using scanning tunneling microscopy and spectroscopy (STM/STS) on the cleaved (110) surface of sulfur-doped n-type InAs at liquid nitrogen temperature. We observe charge state transitions of a single donor impurity residing in the near-surface region from +1 (D⁺) to 0 (D⁰), and subsequently to −1 (DX⁻), as the applied bias voltage increases and exceeds the thresholds for Fröhlich interaction and avalanche breakdown. Furthermore, we report that the effective Fermi level, which governs the donor charge states, is determined by two inelastic processes involving electron doping at 78 K: optical phonon scattering of tunnel electrons and secondary electron generation via impact-ionization.

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