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Your search keyword '"TAKAFUMI SATO"' showing total 4 results
Start Over Author "TAKAFUMI SATO" Journal applied physics letters
4 results on '"TAKAFUMI SATO"'

1. Emergence of undulating surface band upon oxygen adsorption of Fe thin film on W(110)

Author

Takafumi Sato, Takashi Takahashi, Kohei Honma, Seigo Souma, Masahito Tsujikawa, and Masafumi Shirai

Subjects
Materials science, Physics and Astronomy (miscellaneous), Photoemission spectroscopy, Fermi level, Analytical chemistry, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Condensed Matter::Materials Science, symbols.namesake, Adsorption, 0103 physical sciences, Monolayer, symbols, Physics::Chemical Physics, Thin film, 010306 general physics, 0210 nano-technology, Electronic band structure, Dispersion (chemistry), Surface states
Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy of oxygen-adsorbed Fe thin films on W(110) to elucidate the evolution of electronic states upon surface oxidation. After oxygen adsorption of 0.25 monolayer onto Fe films, we found a surface state in the vicinity of the Fermi level which exhibits an undulating energy band dispersion. Our first-principles band-structure calculation indicates that this state is attributed to the spin-polarized minority band arising from the hybridization between Fe 3d and O 2p orbitals. The present result suggests that the observed surface state is related to the unusual magnetic properties of oxidized Fe surfaces.

Published
2017
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2. Work function of bulk-insulating topological insulator Bi2–xSbxTe3–ySey

Author

Daichi Takane, Seigo Souma, Takafumi Sato, Takashi Takahashi, Kouji Segawa, and Yoichi Ando

Subjects
Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Strongly Correlated Electrons (cond-mat.str-el), Physics and Astronomy (miscellaneous), Condensed matter physics, Photoemission spectroscopy, Semiconductor materials, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, Antimony compounds, 01 natural sciences, Condensed Matter - Strongly Correlated Electrons, Topological insulator, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Energy shift, Surface chemical, Work function, Electronics, 010306 general physics, 0210 nano-technology
Abstract

Recent discovery of bulk insulating topological insulator (TI) Bi2-xSbxTe3-ySey paved a pathway toward practical device application of TIs. For realizing TI-based devices, it is necessary to contact TIs with a metal. Since the band-bending at the interface dominates the character of devices, knowledge of TIs' work function is of essential importance. We have determined the compositional dependence of work function in Bi2-xSbxTe3-ySey by high-resolution photoemission spectroscopy. The obtained work-function values (4.95-5.20 eV) show a systematic variation with the composition, well tracking the energy shift of the surface chemical potential seen by angle-resolved photoemission spectroscopy. The present result serves as a useful guide for developing TI-based electronic devices., Comment: 4pages, 2 figures

Published
2016
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3. Emergence of undulating surface band upon oxygen adsorption of Fe thin film on W(110).

Author

Seigo Souma, Kohei Honma, Takafumi Sato, Masahito Tsujikawa, Masafumi Shirai, and Takashi Takahashi

Subjects
PHOTOELECTRON spectroscopy, THIN films, TRANSITION metals, IRON oxidation, MOLECULAR orbitals
Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy of oxygen-adsorbed Fe thin films on W(110) to elucidate the evolution of electronic states upon surface oxidation. After oxygen adsorption of 0.25 monolayer onto Fe films, we found a surface state in the vicinity of the Fermi level which exhibits an undulating energy band dispersion. Our first-principles band-structure calculation indicates that this state is attributed to the spin-polarized minority band arising from the hybridization between Fe 3d and O 2p orbitals. The present result suggests that the observed surface state is related to the unusual magnetic properties of oxidized Fe surfaces. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

4. Work function of bulk-insulating topological insulator Bi2-xSbxTe3-ySey.

Author

Daichi Takane, Seigo Souma, Takafumi Sato, Takashi Takahashi, Kouji Segawa, and Yoichi Ando

Subjects
TOPOLOGICAL insulators, ELECTRON work function, CHEMICAL potential, ELECTRONIC equipment, PHOTOELECTRON spectroscopy
Abstract

Recent discovery of bulk insulating topological insulator (TI) Bi2-xSbxTe3-ySey paved a pathway toward practical device application of TIs. For realizing TI-based devices, it is necessary to contact TIs with a metal. Since the band-bending at the interface dominates the character of devices, knowledge of TIs' work function is of essential importance. We have determined the compositional dependence of the work function in Bi2-xSbxTe3-ySey by high-resolution photoemission spectroscopy. The obtained work-function values (4.95-5.20 eV) track the energy shift of the surface chemical potential seen by angle-resolved photoemission spectroscopy. The present result serves as a useful guide for developing TI-based electronic devices. [ABSTRACT FROM AUTHOR]

Published
2016
Full Text
View/download PDF

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