STM studies of a ferromagnetic monolayer compound and three-dimensional topological insulators

Fumio Komori

Institute for Solid State Physics, University of Tokyo

We have studied a ferromagnetic monolayer compound, Fe2N on the Cu(001) surface, and three-dimensional topological insulators (TI) by using scanning tunneling microscopy/spectroscopy. For the iron nitride, we found orbital-dependent change of the tunneling by changing the tip-surface distance.[1] We have further investigated magnetism of this system using soft X-ray magnetic circular dichroism. For an intrinsic TI, Bi1.5Sb0.5Te1.7Se1.3, we clarified suppression of electron back scattering in the helically spin-polarized surface state using quasi-particle interference (QPI) detection and time-resolve ARPES measurements.[2]. Unoccupied band structures were also investigated in another TI, BixSb(1-x), by QPI. [3]

1. Y. Takahashi et. al., Phys. Rev. Lett. 116, 056802 (2016).

2. S. Kim et. al., Phys. Rev. Lett. 112, 136802 (2014).

3. S. Yishizawa et. al., Phys. Rev. B91, 045423 (2015).

Fumio Komori received his Ph.D. in Physics under Prof. W. Sasaki in 1983 from the University of Tokyo. Then he held a postdoctoral fellowship from Japan Society for Promotion of Science and worked at the same university with Prof. S. Kobayashi. From the end of 1983 to 1990, he was a research associate in the group of Prof. S. Ikehata at the Department of Physics, the University of Tokyo. During those periods, his major was low-temperature physics, in particular, electronic and magnetic properties of metallic thin films, semiconductors, mesoscopic systems and nano-particles. In 1991, he moved to the Institute for Solid State Physics, the University of Tokyo, and started surface science in collaboration with Prof. Y. Murata and Prof. K. Tanaka. Komori studies electronic and magnetic properties of metal and semiconductor surfaces and nanostructures at surfaces using scanning tunneling microscopy and photoemission spectroscopy as main tools. He currently serves as a vice director of the institute from April, 2013, and as an editor of Surface Science, Elsevier (from April, 2007). He served on the editorial board of the Journal of Physical Society of Japan (1992-2004).

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