研究者業績
基本情報
- 所属
- 兵庫県立大学 理学研究科 物質科学専攻 教授大阪大学 基礎工学研究科 物質創成専攻 准教授
- 学位
- 理学博士(東京大学)理学修士(東京大学)
- J-GLOBAL ID
- 200901089608768091
- researchmap会員ID
- 1000185126
研究キーワード
4経歴
5-
2021年4月 - 現在
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2007年4月 - 2021年3月
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2003年4月 - 2007年3月
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1999年1月 - 2003年3月
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1994年4月 - 1998年12月
受賞
1-
2003年
論文
173-
Scientific Reports 14(1) 2024年5月8日Abstract Topological insulators (TI) hold significant potential for various electronic and optoelectronic devices that rely on the Dirac surface state (DSS), including spintronic and thermoelectric devices, as well as terahertz detectors. The behavior of electrons within the DSS plays a pivotal role in the performance of such devices. It is expected that DSS appear on a surface of three dimensional(3D) TI by mechanical exfoliation. However, it is not always the case that the surface terminating atomic configuration and corresponding band structures are homogeneous. In order to investigate the impact of surface terminating atomic configurations on electron dynamics, we meticulously examined the electron dynamics at the exfoliated surface of a crystalline 3D TI (Bi$$_2$$Se$$_3$$) with time, space, and energy resolutions. Based on our comprehensive band structure calculations, we found that on one of the Se-terminated surfaces, DSS is located within the bulk band gap, with no other surface states manifesting within this region. On this particular surface, photoexcited electrons within the conduction band effectively relax towards DSS and tend to linger at the Dirac point for extended periods of time. It is worth emphasizing that these distinct characteristics of DSS are exclusively observed on this particular surface.
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Beilstein Journal of Organic Chemistry 20 570-577 2024年3月11日We theoretically analyze possible multiple conformations of protein molecules immobilized by 1-pyrenebutanoic acid succinimidyl ester (PASE) linkers on graphene. The activation barrier between two bi-stable conformations exhibited by PASE is confirmed to be based on the steric hindrance effect between a hydrogen on the pyrene group and a hydrogen on the alkyl group of this molecule. Even after the protein is supplemented, this steric hindrance effect remains if the local structure of the linker consisting of an alkyl group and a pyrene group is maintained. Therefore, it is likely that the kinetic behavior of a protein immobilized with a single PASE linker exhibits an activation barrier-type energy surface between the bi-stable conformations on graphene. We discuss the expected protein sensors when this type of energy surface appears and provide a guideline for improving the sensitivity, especially as an oscillator-type biosensor.
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Physical Chemistry Chemical Physics 26(12) 9733-9740 2024年3月6日Enhanced spin control in graphene/hBN MTJ: boron vacancy tuning yields high TMR ratio of 400%, paving the way for ultra-thin spin valves.
MISC
259-
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 42(37) 23691-23697 2017年9月 査読有りWe investigated the minimum energy pathways and energy barriers of reversible reaction (V-111 + H-2 <-> V-221) based upon calculations using density functional theory. We find a comparable activation barrier of around 1.3 eV for both the dissociative chemisorption and desorption processes. The charge transfer rate from a reacting hydrogen atom to the graphene is around 0.18 e per hydrogen atom in the final state. A subsequent reaction path to recover the initial structure of V-111 is realized by the migration of hydrogen atoms from V-221 onto the graphene surface. The comparable energy barrier of 1.3 eV for both adsorption and desorption suggests that this novel storage and release concept has the potential to act as a hydrogen storage system for certain applications. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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2014年12月30日Electron correlation effects caused by the topological zero mode of a<br /> hydrogenated graphene vacancy, $V_{111}$, with three adsorbed hydrogen atoms is<br /> discussed theoretically. A Kondo model is derived from the multi-reference<br /> representation of the density functional theory, where exchange scattering<br /> processes between the zero mode and low-energy modes in the Dirac cones are<br /> estimated. Even when the Dirac cone is slightly off from the charge neutral<br /> point, a finite on-site correlation energy, $U_0$, for the zero mode of an<br /> isolated $V_{111}$ allows the half-filling of the localized level giving a spin<br /> $s=1/2$. The anti-ferromagnetic Kondo screening mediated by higher order<br /> scattering processes becomes dominant in the dilute limit of the vacancies. Our<br /> estimation of relevant two body interactions certifies appearance of the Kondo<br /> effect at low temperatures.
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日本物理学会講演概要集 69(2) 624-624 2014年8月22日
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日本物理学会講演概要集 69(2) 601-601 2014年8月22日
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Phys. Rev. B 89 224505(2014) 2014年3月11日By constructing $d_{x^2-y^2}-d_{z^2}$ two-orbital models from first<br /> principles, we have obtained a systematic correlation between the Fermi surface<br /> warping and the evaluated $T_c$ for various bilayer as well as single-layer<br /> cuprates. This reveals that smaller mixture of the $d_{z^2}$ orbital component<br /> on the Fermi surface leads to both of larger Fermi surface warping and higher<br /> $T_c$. The theoretical correlation strikingly resembles a systematic plot for<br /> the experimentally observed $T_c$ against the Fermi surface warping due to<br /> Pavarini {\it et al.} [Phys. Rev. Lett. {\bf 87}, 047003 (2001)], and the<br /> present result unambiguously indicates that the $d_{z^2}$ mixture is a key<br /> factor that determines $T_c$ in the cuprates.
書籍等出版物
5-
Jenny Stanford Pub. 2019年11月 (ISBN: 9789814800389)
Works(作品等)
8共同研究・競争的資金等の研究課題
37-
日本学術振興会 科学研究費助成事業 2022年4月 - 2025年3月
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日本学術振興会 科学研究費助成事業 2021年4月 - 2024年3月
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日本学術振興会 科学研究費助成事業 2019年4月 - 2023年3月
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日本学術振興会 科学研究費助成事業 2018年4月 - 2021年3月
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日本学術振興会 科学研究費助成事業 2016年4月 - 2018年3月