Tatsuki Oda - Academia.edu (original) (raw)

Papers by Tatsuki Oda

Research paper thumbnail of Order-N tight-binding molecular dynamics with a Fermi operator expansion: Application to liquid carbons

Research paper thumbnail of Chain structure of liquid and amorphous selenium: tight-binding molecular-dynamics simulation

Journal of Non-crystalline Solids, Aug 1, 1999

Tight-binding molecular-dynamics (TB-MD) simulation has been performed to study the properties on... more Tight-binding molecular-dynamics (TB-MD) simulation has been performed to study the properties on the microscopic scale of liquid and amorphous selenium at 375 and 760 K. Since a diagonalization of the tight-binding (TB) Hamiltonian matrix is time consuming calculation, we have made parallel computations in the simulation program to realize a long time simulation of 512 atoms up to the 10 5 time steps corresponding to the order of 10 ps. The result shows that the radial distribution function, which becomes zero at around 0.275 nm, agrees with experiments and the dihedral angle distribution function has a maximum around 0°, a minimum at 30°and a smaller maximum around 100°. This tendency diers from a previous study either by the tight-binding Monte Carlo (TB-MC) simulation or by the ®rst principle molecular-dynamics (MD) simulation.

Research paper thumbnail of Implementation of Parallel Matrix Diagonalization for Ab-Initio Molecular Dynamics Program Using Scalapack

Research paper thumbnail of The electric states and the structural phase transition of the monoclinic selenium under high pressure

Research paper thumbnail of 28aSC-8 擬ポテンシャル法による磁気異方性エネルギーの見積り(28aSC 領域9,領域3合同 表面・界面磁性,領域9(表面・界面,結晶成長))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2006

Research paper thumbnail of 18pAF-4 遺伝的アルゴリズムによる固体アルゴンの結晶構造探索

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2015

Research paper thumbnail of 9aAK-5 First principles calculation on magnetic anisotropy and its electric field effect in the double interface MgO/Fe/MgO

Research paper thumbnail of Intrinsic instability to martensite phases in ferromagnetic shape memory alloy Ni2MnGa : Quasiparticle self-consistent GW investigation

Physical Review Materials

We investigated the electronic structure of a ferromagnetic shape memory alloy Ni 2 MnGa utilizin... more We investigated the electronic structure of a ferromagnetic shape memory alloy Ni 2 MnGa utilizing an advanced approach, quasiparticle self-consistent GW , which takes account of electron localization effects without empirical parameters. The Ni e g orbitals in the cubic phase, which lead to martensite phase transition, were found to locate on the Fermi level, implying a clear definitive origin of band Jahn-Teller (JT) effect in comparison with the results obtained by the density functional approach of generalized gradient approximation. From the analysis of generalized susceptibility in the cubic phase, the instabilities responsible for the modulated structures of 10M, 14M, and 6M were found to be an intrinsic property in the electronic states. These states may stabilize the modulated one, accompanied by tetragonal local JT distortions. Their property of Fermi surface nesting sensitively depends on a subtle change in the magnetic moment, corresponding to the experimental fact that the modulated structure appears depending on temperature and the composition of the magnetic element. The secondary nesting vector along [110] direction was discussed in relation to a modulation alignment of the nanotwin boundary.

Research paper thumbnail of 26pPSB-10 Tl積層Si(111)表面における相対論的第一原理電子状態計算(26pPSB 領域9ポスターセッション,領域9(表面・界面,結晶成長))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2012

Research paper thumbnail of 23aPS-127 膜透過ペプチドによる脂質二重膜の変形(23aPS 領域12ポスターセッション,領域12(ソフトマター物理,化学物理,生物物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2010

Research paper thumbnail of 31a-Q-9 Calculation of Selenium chain electronic structure

Research paper thumbnail of 28aGV-11 膜透過ペプチドによる逆ミセル形成における電荷の影響 : 粗視化シミュレーション(28aGV 生物物理,領域12(ソフトマター物理,化学物理,生物物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2011

Research paper thumbnail of Implementation of Magnetic Dipole Interaction in the Planewave-Basis Approach for Slab Systems

Journal of the Physical Society of Japan, 2018

We implemented the magnetic dipole interaction (MDI) in a first-principles planewave-basis electr... more We implemented the magnetic dipole interaction (MDI) in a first-principles planewave-basis electronic structure calculation based on spin density functional theory. This implementation, employing t...

Research paper thumbnail of 26pXF-11 第一原理遺伝的アルゴリズムによるイットリウム高圧相の探索(26pXF 高圧物性,領域7(分子性固体・有機導体))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2013

Research paper thumbnail of 21aPS-76 Development of two component spinor type ultrasoft pseudopotential

Research paper thumbnail of The structural phase transition and electronic structure of selenium under high pressure

Research paper thumbnail of Anatomy of large perpendicular magnetic anisotropy in free-standing Co/Ni (1 1 1) multilayer

Journal of Magnetism and Magnetic Materials, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Noncollinear Magnetic Structure with Spin-dependent van der Waals Density Functional Approach: β-phase Solid Oxygen

Journal of the Physical Society of Japan, 2019

We developed and implemented the van der Waals density functional with noncollinear magnetism. To... more We developed and implemented the van der Waals density functional with noncollinear magnetism. To demonstrate the validity of the current implementation, we applied the method to the β-phase of sol...

Research paper thumbnail of Density functional study on positively charged six-coordinate FeO2 porphyrin complex for a trigger of O2 dissociation

Chemical Physics Letters, 2016

Abstract Properties on electronic structure in an Fe-porphyrin (FeP) complex with the proximal im... more Abstract Properties on electronic structure in an Fe-porphyrin (FeP) complex with the proximal imidazole (Im) ligand, a model of active moiety of hemeprotein for analyzing bonding- and separating-processes of dioxygen molecule (O 2 ), were studied by means of spin-polarized density functional theory. It was found that in the ionized model, the bonding stability of O 2 was reduced by one order in energy compared with that of the neutral model, implying existence of the state having a large fluctuation between bonded and separated configurations. We proposed a microscopic scenario on O 2 dissociation phenomenon in terms of spin-crossover and allosteric mechanism.

Research paper thumbnail of Molecular Interactions for Modeling of Oxygen System Using van der Waals Density Functional Approach

Proceedings of Computational Science Workshop 2014 (CSW2014), 2015

We investigated oxygen molecular systems of T-type, X-type, and S-type using the method with van ... more We investigated oxygen molecular systems of T-type, X-type, and S-type using the method with van der Waals density functional and spin-polarization dependent gradient correction. In the S-type configuration, the magnetic interaction showed a characteristic behavior with respect to the structural parameter of the angle, θ, that is formed by the molecular axis and intermolecular axis. It was found that there was a range of θ in which the magnetic interaction vanished at short intermolecular distances.

Research paper thumbnail of Order-N tight-binding molecular dynamics with a Fermi operator expansion: Application to liquid carbons

Research paper thumbnail of Chain structure of liquid and amorphous selenium: tight-binding molecular-dynamics simulation

Journal of Non-crystalline Solids, Aug 1, 1999

Tight-binding molecular-dynamics (TB-MD) simulation has been performed to study the properties on... more Tight-binding molecular-dynamics (TB-MD) simulation has been performed to study the properties on the microscopic scale of liquid and amorphous selenium at 375 and 760 K. Since a diagonalization of the tight-binding (TB) Hamiltonian matrix is time consuming calculation, we have made parallel computations in the simulation program to realize a long time simulation of 512 atoms up to the 10 5 time steps corresponding to the order of 10 ps. The result shows that the radial distribution function, which becomes zero at around 0.275 nm, agrees with experiments and the dihedral angle distribution function has a maximum around 0°, a minimum at 30°and a smaller maximum around 100°. This tendency diers from a previous study either by the tight-binding Monte Carlo (TB-MC) simulation or by the ®rst principle molecular-dynamics (MD) simulation.

Research paper thumbnail of Implementation of Parallel Matrix Diagonalization for Ab-Initio Molecular Dynamics Program Using Scalapack

Research paper thumbnail of The electric states and the structural phase transition of the monoclinic selenium under high pressure

Research paper thumbnail of 28aSC-8 擬ポテンシャル法による磁気異方性エネルギーの見積り(28aSC 領域9,領域3合同 表面・界面磁性,領域9(表面・界面,結晶成長))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2006

Research paper thumbnail of 18pAF-4 遺伝的アルゴリズムによる固体アルゴンの結晶構造探索

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2015

Research paper thumbnail of 9aAK-5 First principles calculation on magnetic anisotropy and its electric field effect in the double interface MgO/Fe/MgO

Research paper thumbnail of Intrinsic instability to martensite phases in ferromagnetic shape memory alloy Ni2MnGa : Quasiparticle self-consistent GW investigation

Physical Review Materials

We investigated the electronic structure of a ferromagnetic shape memory alloy Ni 2 MnGa utilizin... more We investigated the electronic structure of a ferromagnetic shape memory alloy Ni 2 MnGa utilizing an advanced approach, quasiparticle self-consistent GW , which takes account of electron localization effects without empirical parameters. The Ni e g orbitals in the cubic phase, which lead to martensite phase transition, were found to locate on the Fermi level, implying a clear definitive origin of band Jahn-Teller (JT) effect in comparison with the results obtained by the density functional approach of generalized gradient approximation. From the analysis of generalized susceptibility in the cubic phase, the instabilities responsible for the modulated structures of 10M, 14M, and 6M were found to be an intrinsic property in the electronic states. These states may stabilize the modulated one, accompanied by tetragonal local JT distortions. Their property of Fermi surface nesting sensitively depends on a subtle change in the magnetic moment, corresponding to the experimental fact that the modulated structure appears depending on temperature and the composition of the magnetic element. The secondary nesting vector along [110] direction was discussed in relation to a modulation alignment of the nanotwin boundary.

Research paper thumbnail of 26pPSB-10 Tl積層Si(111)表面における相対論的第一原理電子状態計算(26pPSB 領域9ポスターセッション,領域9(表面・界面,結晶成長))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2012

Research paper thumbnail of 23aPS-127 膜透過ペプチドによる脂質二重膜の変形(23aPS 領域12ポスターセッション,領域12(ソフトマター物理,化学物理,生物物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2010

Research paper thumbnail of 31a-Q-9 Calculation of Selenium chain electronic structure

Research paper thumbnail of 28aGV-11 膜透過ペプチドによる逆ミセル形成における電荷の影響 : 粗視化シミュレーション(28aGV 生物物理,領域12(ソフトマター物理,化学物理,生物物理))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2011

Research paper thumbnail of Implementation of Magnetic Dipole Interaction in the Planewave-Basis Approach for Slab Systems

Journal of the Physical Society of Japan, 2018

We implemented the magnetic dipole interaction (MDI) in a first-principles planewave-basis electr... more We implemented the magnetic dipole interaction (MDI) in a first-principles planewave-basis electronic structure calculation based on spin density functional theory. This implementation, employing t...

Research paper thumbnail of 26pXF-11 第一原理遺伝的アルゴリズムによるイットリウム高圧相の探索(26pXF 高圧物性,領域7(分子性固体・有機導体))

Meeting Abstracts of the Physical Society of Japan (Nihon Butsuri Gakkai koen gaiyoshu), 2013

Research paper thumbnail of 21aPS-76 Development of two component spinor type ultrasoft pseudopotential

Research paper thumbnail of The structural phase transition and electronic structure of selenium under high pressure

Research paper thumbnail of Anatomy of large perpendicular magnetic anisotropy in free-standing Co/Ni (1 1 1) multilayer

Journal of Magnetism and Magnetic Materials, 2019

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of Noncollinear Magnetic Structure with Spin-dependent van der Waals Density Functional Approach: β-phase Solid Oxygen

Journal of the Physical Society of Japan, 2019

We developed and implemented the van der Waals density functional with noncollinear magnetism. To... more We developed and implemented the van der Waals density functional with noncollinear magnetism. To demonstrate the validity of the current implementation, we applied the method to the β-phase of sol...

Research paper thumbnail of Density functional study on positively charged six-coordinate FeO2 porphyrin complex for a trigger of O2 dissociation

Chemical Physics Letters, 2016

Abstract Properties on electronic structure in an Fe-porphyrin (FeP) complex with the proximal im... more Abstract Properties on electronic structure in an Fe-porphyrin (FeP) complex with the proximal imidazole (Im) ligand, a model of active moiety of hemeprotein for analyzing bonding- and separating-processes of dioxygen molecule (O 2 ), were studied by means of spin-polarized density functional theory. It was found that in the ionized model, the bonding stability of O 2 was reduced by one order in energy compared with that of the neutral model, implying existence of the state having a large fluctuation between bonded and separated configurations. We proposed a microscopic scenario on O 2 dissociation phenomenon in terms of spin-crossover and allosteric mechanism.

Research paper thumbnail of Molecular Interactions for Modeling of Oxygen System Using van der Waals Density Functional Approach

Proceedings of Computational Science Workshop 2014 (CSW2014), 2015

We investigated oxygen molecular systems of T-type, X-type, and S-type using the method with van ... more We investigated oxygen molecular systems of T-type, X-type, and S-type using the method with van der Waals density functional and spin-polarization dependent gradient correction. In the S-type configuration, the magnetic interaction showed a characteristic behavior with respect to the structural parameter of the angle, θ, that is formed by the molecular axis and intermolecular axis. It was found that there was a range of θ in which the magnetic interaction vanished at short intermolecular distances.