出倉　春彦 (デクラ　ハルヒコ)

研究者情報

学位

• 博士（理学）（大阪大学）

科研費研究者番号

• 90700146

J-Global ID

• 201601005071337940

研究キーワード

• 地球内部物質科学   計算物理学   物性理論   固体電子論   フォノン   輸送現象   第一原理計算   

研究分野

• 自然科学一般 / 固体地球科学 / 内部ダイナミクス・物性
• 自然科学一般 / 固体地球科学 / 鉱物物理
• 自然科学一般 / 磁性、超伝導、強相関系 / 金属
• 自然科学一般 / 半導体、光物性、原子物理 / 半導体
• 自然科学一般 / 半導体、光物性、原子物理 / フォノン物性
• 自然科学一般 / 数理物理、物性基礎 / 計算物理学

経歴

• 2016年04月 - 現在  愛媛大学地球深部ダイナミクス研究センター講師
• 2013年01月 - 2016年03月  愛媛大学地球深部ダイナミクス研究センター助教
• 2010年04月 - 2012年12月  愛媛大学上級研究員センター博士研究員
• 2010年03月  エコールポリテクニック理論物質科学博士研究員

学歴

•         - 2010年   大阪大学   大学院理学研究科   物理学専攻
•         - 2005年   中央大学   理工学部   物理学科
•         - 2000年   柏日体高等学校 (現 日本体育大学柏高等学校）

所属学協会

• アメリカ地球物理学連合   日本地球惑星科学連合   日本結晶学会   日本高圧力学会   日本シミュレーション学会   日本物理学会   

研究活動情報

論文

• Ab Initio Study on the Lower Mantle Minerals

  Taku Tsuchiya, Jun Tsuchiya, Haruhiko Dekura, Sebastian Ritterbex

  Annual Review of Earth and Planetary Sciences 48 1 2020年05月 [査読有り]
   研究論文（学術雑誌）
• Lattice thermal conductivity of MgSiO3 postperovskite under the lowermost mantle conditions from ab initio anharmonic lattice dynamics

  Haruhiko Dekura, Taku Tsuchiya

  Geophysical Research Letters 46 22 12919 - 12926 2019年 [査読有り]
   研究論文（学術雑誌）
• Ab initio lattice thermal conductivity of MgO from a complete solution of the linearized Boltzmann transport equation

  Haruhiko Dekura, Taku Tsuchiya

  Physical Review B 95 18 2017年05月 研究論文（学術雑誌） 

  Lattice thermal conductivity κlat of MgO at high pressures P and temperatures T up to 150 GPa and 4000 K are determined using lattice dynamics calculations and the linearized phonon Boltzmann transport equation (BTE) beyond the relaxation time approximation (RTA) from first principles. It is found that the complete solution of the linearized BTE substantially corrects values of κlat calculated with the RTA by ∼30%, from ∼42 to ∼54Wm-1K-1 under ambient conditions. The calculated values of κlat are in good agreement with those from the existing experiments. At conditions representative of the Earth's core-mantle boundary (P=136GPa and T=3800K), κlat is predicted to be ∼32 and ∼40Wm-1K-1 by RTA and the full solution of BTE, respectively. We report a detailed comparison of our study with earlier theoretical studies.
• Ab initio lattice thermal conductivity of MgO from a complete solution of the linearized Boltzmann transport equation

  Haruhiko Dekura, Taku Tsuchiya

  Physical Review B 18 95 184303  2017年05月 研究論文（学術雑誌） 

  Lattice thermal conductivity κlat of MgO at high pressures P and temperatures T up to 150 GPa and 4000 K are determined using lattice dynamics calculations and the linearized phonon Boltzmann transport equation (BTE) beyond the relaxation time approximation (RTA) from first principles. It is found that the complete solution of the linearized BTE substantially corrects values of κlat calculated with the RTA by ∼30%, from ∼42 to ∼54 W m−1 K−1 under ambient conditions. The calculated values of κlat are in good agreement with those from the existing experiments. At conditions representative of the Earth’s core-mantle boundary (P = 136 GPa and T = 3800 K), κlat is predicted to be ∼32 and ∼40 W m−1 K−1 by RTA and the full solution of BTE, respectively. We report a detailed comparison of our study with earlier theoretical studies.
• Structure and stability of pseudo-cubic tetragonal boron

  Koun Shirai, Naoki Uemura, Haruhiko Dekura

  Japanese Journal of Applied Physics 56 05FB05  2017年04月 [査読有り]
   研究論文（学術雑誌）
• Experimental and theoretical thermal equations of state of MgSiO3 post-perovskite at multi-megabar pressures

  Takeshi Sakai, Haruhiko Dekura, Naohisa Hirao

  SCIENTIFIC REPORTS 6 2016年03月 研究論文（学術雑誌） 

  The MgSiO3 post-perovskite phase is the most abundant silicate phase in a super-Earth's mantle, although it only exists within the Earth's lowermost mantle. In this study, we established the thermal equation of state (EoS) of the MgSiO3 post-perovskite phase, which were determined by using both laser-heated diamond anvil cell and density-functional theoretical techniques, within a multi-megabar pressure range, corresponding to the conditions of a super-Earth's mantle. The Keane and AP2 EoS models were adopted for the first time to extract meaningful physical properties. The experimentally determined Gruneisen parameter, which is one of the thermal EoS parameters, and its volume dependence were found to be consistent with their theoretically obtained values. This reduced the previously reported discrepancy observed between experiment and theory. Both the experimental and theoretical EoS were also found to be in very good agreement for volumes at pressures and temperatures of up to 300 GPa and 5000 K, respectively. Our newly developed EoS should be applicable to a super-Earth's mantle, as well as the Earth's core-mantle boundary region.
• Temperature of the Lower Mantle and Core Based on Ab Initio Mineral Physics Data

  Tsuchiya Taku, Kawai Kenji, Wang Xianlong, Ichikawa Hiroki, Dekura Haruhiko

  Deep Earth: Physics and Chemistry of the Lower Mantle and Core 217 13 - 30 2016年 [査読有り]
  
• Theoretical and experimental evidence for the post-cotunnite phase transition in zirconia at high pressure

  Daisuke Nishio-Hamane, Haruhiko Dekura, Yusuke Seto, Takehiko Yagi

  PHYSICS AND CHEMISTRY OF MINERALS 42 5 385 - 392 2015年05月 研究論文（学術雑誌） 

  A post-cotunnite phase transition in zirconia (ZrO2) at high pressure was investigated by synchrotron X-ray diffraction measurements and ab initio calculations based on density functional theory. This study successfully demonstrated a cotunnite- to Fe2P-type phase transition. Static enthalpy difference (Delta H) calculations predicted the appearance of the Fe2P phase at 124 GPa (LDA) and 143 GPa (GGA), and experimental trials demonstrated the coexistence of the Fe2P and cotunnite phases at 175 GPa after heating to 3,000 K. Both phases were quenchable to ambient conditions. The volume of the Fe2P phase was slightly less (similar to Delta 0.6 %) than that of the cotunnite phase over the experimental pressure range, indicating that the Fe2P phase is the higher pressure phase. The coexistence of both phases in this study may be attributed to the slow kinetics of the phase transition resulting from the close structural relationship of the two phases. An Fe2P-type structural model can be derived by applying a simple operation to the cotunnite-type structure, consisting of a 1/2 shift of several zirconium arrangements parallel to the b-axis of the cotunnite-type unit cell. It is concluded that the high-pressure cotunnite-to-Fe2P phase transition may be a common trend in many dioxides.
• Ab initio lattice thermal conductivity of MgSiO3perovskite as found in earth's lower mantle

  Dekura, H., Tsuchiya, T., Tsuchiya, J.

  Physical Review Letters 110 2 2013年 研究論文（学術雑誌） 

  The lattice thermal conductivity (κlat) of MgSiO 3 perovskite (Mg-Pv) under high-pressure and high-temperature conditions was computed based on the ab initio anharmonic lattice dynamics method with the density functional perturbation theory. κlat of Mg-Pv is found to increase with increasing pressure from 9.8 (at 23.5 GPa) to 43.6 W m-1 K-1 (at 136 GPa) at 300 K, while decreasing with increasing temperature from 28.1 (at 300 K) to 2.3 W m-1 K -1 (at 4000 K) at 100 GPa. A multiphase composite average yielded a mantle Rayleigh number adequate to promote the vigorous thermal convection of the mantle that is expected geophysically. © 2013 American Physical Society.
• Phase relations in boron at pressures up to 18 GPa and temperatures up to 2200 °c

  Jiaqian Qin, Tetsuo Irifune, Haruhiko Dekura, Hiroaki Ohfuji, Norimasa Nishiyama, Li Lei, Toru Shinmei

  Physical Review B - Condensed Matter and Materials Physics 85 2012年01月 

  The phase relations in boron have been investigated at high pressure and high temperature using a multianvil apparatus, and the quenched sample has been analyzed by x-ray diffraction, Raman spectra, and transmission electron microscopy. We demonstrate that γ-B 28 can be synthesized over a wide pressure and temperature range, and α-tetragonal B 50 (T-B 50) is obtained at higher temperatures and similar pressures. The phase boundary of the β-B 106, γ-B 28, and T-B 50 is determined at pressures between 7.0 and 18 GPa and the temperatures of 500-2200 C. The results suggest that T-B 50 might be an intermediate phase formed for kinetic reasons (Ostwald rule) on the way from β-B 106 to β-tetragonal B 192 (T-192) and γ-B 28 to T-192. © 2012 American Physical Society.
• Efficient method for Li doping of α-rhombohedral boron

  H. Dekura, K. Shirai, A. Yanase

  Physical Review B - Condensed Matter and Materials Physics 84 9  - DH000155 2011年09月 研究論文（学術雑誌） 

  Li doping is a promising method for achieving metallization of α-rhombohedral boron (α-boron for short), which is a potential candidate for a high-Tc superconducting material. Toward this end, a serious drawback has been the difficulty of doping α-boron, even though there are theoretical predictions claiming that it should be easy. This discrepancy has been systematically studied by the ab initio pseudopotential method through calculations of various structural and phonon properties of the material. For this study, a comparison with β-boron is important because experimental data are available in this case. The present results demonstrate that while Li doping is difficult for α-boron under normal conditions, it is easy for β-boron, which is completely consistent with experiments. The difference between these crystals originates from the contrasting characteristics of the bonding. For α-boron, the bonding requirement of the host crystal is fulfilled so well that the only way for a Li atom to enter the crystal is through the antibonding states. Electronically, this is favorable because it causes an almost perfect rigid-band shift without modifying the bonding nature of the host crystal. In terms of structural effects, Li doping causes a slight decrease in the cell angle αrh as well as softening of the elastic properties. A striking effect of Li doping is manifested in substantial phonon softening of the librational mode. These changes can be regarded as reliable criteria for the experimental detection of Li inclusion. On the other hand, β-boron can be characterized as a frustrated system, and the crystal has a propensity to welcome guest atoms in order to eliminate ill-connected bonds. As a result, even though Li is easily incorporated into β-boron, the carriers are not activated for electrical conduction. The remaining problem is how to overcome the difficulty of Li doping of α-boron. The most important contribution of this study lies in demonstrating the usefulness of high-pressure synthesis as an efficient doping method. © 2011 American Physical Society.
• Structural study of α-rhombohedral boron at high pressures

  Koun Shirai, Haruhiko Dekura, Yoshihisa Mori, Yutaka Fujii, Hiroshi Hyodo, Kaoru Kimura

  Journal of the Physical Society of Japan 80 8 2011年08月 研究論文（学術雑誌） 

  Recently, it has been shown that, like β-rhombohedral boron (β-boron), α-rhombohedral boron (α-boron) exhibits superconductivity at high pressure. The transition pressure is similar to that of β-boron, that is, about 160 GPa. This paper presents a theoretical and experimental study of the structural change in α-boron at high pressures. High-pressure (up to 200 GPa) X-ray experiments were performed at a synchrotron-radiation facility. At ambient temperature, the crystal of α-boron is stable over the whole range of pressures examined. There is no phase transitions, such as to α-Ga type, which were previously predicted. All the structural parameters vary continuously with pressure. The cause of metallization is a significant contraction of the intericosahedral three-center bond, which brings a higher coordination to the icosahedron and a transfer of charge from the intraicosahedoral bond to the three-center bond. Although everything is continuous, a careful analysis of the pressure dependence of the structural parameters by comparing experiment with ab initio calculation, reveals a characteristic change in the angle of the rhombohedral lattice and some of the internal coordinates of atoms at about 50 GPa. This is the pressure at which the metallization process begins. This structural change can be observed as the step in the pressure dependence of the electrical resistivity and the phonon softening. The interrelationships underlying these changes have been established on theoretical grounds. The long-debated issue of whether the intericosahedral bond is stronger than intraicosahedral bond has been resolved: the traditional understanding that the former is stronger has been proven. A direct piece of evidence for this is the initial deviation of the intericosahedral bond from the lattice vector. © 2011 The Physical Society of Japan.
• Raman scattering and isotopic phonon effects in dodecaborides

  H. Werheit, V. Filipov, K. Shirai, H. Dekura, N. Shitsevalova, U. Schwarz, M. Armbruester

  JOURNAL OF PHYSICS-CONDENSED MATTER 23 6 2011年02月 研究論文（学術雑誌） 

  The Raman spectra of numerous dodecaborides have been measured on high-quality single crystals at ambient conditions with high spectral resolution and signal-to-noise ratio. Besides the strong Raman-active modes, numerous Raman-inactive modes occur in the spectra, indicating distortions of the structures. Ab initio calculation of the phonon spectra on ZrB12 excellently agrees with the experimental results. Force constants are theoretically calculated and force parameters are estimated from the Raman frequencies. The influence of the surface range on the Raman spectra is evident. The different isotopic effects (virtual crystal approximation, the polarization effect and the effect of isotopic disorder) on the phonon frequencies are determined, separated and discussed.
• First-principles prediction of post-pyrite phase transitions in germanium dioxide

  Dekura, H., Tsuchiya, T., Tsuchiya, J.

  Physical Review B - Condensed Matter and Materials Physics 83 13 2011年 研究論文（学術雑誌） 

  Two high-pressure phase transitions in GeO2 have been discovered through first-principles computer simulations: the first is a transition from the pyrite-type (FeS2) to cotunnite-type (α-PbCl2) structure predicted to occur at a pressure of ∼300 GPa, and the second is a transition from the cotunnite-type to the hexagonal Fe2P-type structure at ∼600 GPa. The former is accompanied by a remarkable volume reduction of 5.4%, while the latter has a distinctive but quite small volume change of 0.3%. The post-pyrite transition to the cotunnite-type structure is expected from known high-pressure behavior of other dioxides, while the post-cotunnite transition to an Fe2P-type structure is quite unexpected, with no report in any dioxides so far except for a recent study on SiO2. The Fe2P-type phase has higher effective coordination numbers of Ge atoms, which contributes to stabilizing this structure relative to cotunnite. The results obtained extend our knowledge of the ultrahigh-pressure crystallography of dioxide materials. © 2011 American Physical Society.
• Theoretical and experimental evidence for a new post-cotunnite phase of titanium dioxide with significant optical absorption

  Dekura, H., Tsuchiya, T., Kuwayama, Y., Tsuchiya, J.

  Physical Review Letters 107 4 2011年 研究論文（学術雑誌） 

  We report the discovery of a post-cotunnite phase of TiO2 by both density-functional ab initio calculations and high-pressure experiments. A pressure-induced phase transition to a hexagonal Fe2P-type structure (space group P6̄2m) was predicted to occur at 161 GPa and 0 K and successfully observed by in situ synchrotron x-ray diffraction measurements at 210 GPa and 4000 K with a significant increase in opacity. This change in opacity is attributed to a reduction of band gap from 3.0 to 1.9 eV across the phase change. The Fe2P-type structure is proved to be the densest phase in major metal dioxides. © 2011 American Physical Society.
• Theoretical Investigation on Synthesizing BC5 Crystal

  Nobuya Nakae, Jun Ishisada, Haruhiko Dekura, Koun Shirai

  INTERNATIONAL CONFERENCE ON HIGH PRESSURE SCIENCE AND TECHNOLOGY, JOINT AIRAPT-22 AND HPCJ-50 215 2010年 研究論文（国際会議プロシーディングス） 

  Recent discovery of a compound BC5, whose structure is most likely diamond, invoked intensive interests in the superconductivity research. Little is known not only for its properties but for the preparation methods. For synthesizing BC5, it is very important to know under what conditions this compound can be obtained. In this paper, density-functional-theoretic study has been made on the stability of BC5 relative to a mixture of BC3 and graphite as a function of pressure. It is shown that BC5 becomes stable above 2 GPa. Therefore, high pressure synthesize is very useful.
• Metallicity of boron carbides at high pressure

  Haruhiko Dekura, Koun Shirai, Akira Yanase

  INTERNATIONAL CONFERENCE ON HIGH PRESSURE SCIENCE AND TECHNOLOGY, JOINT AIRAPT-22 AND HPCJ-50 215 2010年 研究論文（国際会議プロシーディングス） 

  Electronic structure of semiconducting boron carbide at high pressure has been theoretically investigated, because of interests in the positive pressure dependence of resistivity, in the gap closure, and in the phase transition. The most simplest form B-12(CCC) is assumed. Under assumptions of hydrostatic pressure and neglecting finite-temperature effects, boron carbide is quite stable at high pressure. The crystal of boron carbide is stable at least until a pressure higher than previous experiments showed. The gap closure occurs only after p = 600 GPa on the assumption of the original crystal symmetry. In the low pressure regime, the pressure dependence of the energy gap almost diminishes, which is an exceptional case for semiconductors, which could be one of reasons for the positive pressure dependence of resistivity. A monotonous increase in the apex angle of rhombohedron suggests that the covalent bond continues to increase. The C chain inserted in the main diagonal of rhombohedral structure is the chief reason of this stability.
• Calculation of fermi surface and its application to li-doped α-boron

  H. Dekura, K. Shirai, A. Yanase

  Journal of Computational and Theoretical Nanoscience 6 12 2629 - 2634 2009年12月 研究論文（学術雑誌） 

  An accurate calculation method for Fermi surfaces is presented in order to study the electronic doping effect to semiconductor a-boron. Given the eigenvalues of energy at a limited set of k points, the present interpolation method retains the original accuracy of the energy eigenvalues, which are provided by a band calculation program. A significant contribution of the present method is to eliminate spurious components in the interpolation which are present in other methods. This is achieved by removal of redundancy in the basis functions. An application is given for doped-semiconductor a-boron, which has recently attracted a growing interest in connection to superconductivity research. Copyright © 2009 American Scientific Publishers All rights reserved.
• Superconductivity research on boron solids and an efficient doping method

  Koun Shirai, Haruhiko Dekura, Akira Masago

  Journal of Physics: Conference Series 176 2009年09月 

  Boron solids are, similar to diamond, strong electron-phonon coupling systems and therefore potentially have high-Tc superconductivity. For realizing high transition temperature Tc, however, careful control of the valence electrons is necessary, which requires detailed understanding of the electronic structure. By critically reviewing recent development in this field, along with the situation in heavily doped diamond and clathrates, we show a promising route for high Tc in boron system. Although both α- and β-boron become metallic and exhibit superconductivity at high pressure, the strong covalent character still remains, which significantly limits its Tc achieved by applying high pressure. Heavy doping of related compounds is desirable, as long as the basic electronic structure is retained, but it is extremely difficult at normal conditions. A promising method to achieve this is high pressure synthesis. Similar technique is useful for heavy doping of diamond. To design high-pressure experiment, the role of theory is important through predicting the phase diagram, which was not available for boron previously. © 2009 IOP Publishing Ltd.
• Metallization of α-boron by hydrogen doping

  Haruhiko Dekura, Koun Shirai, Akira Yanase

  Journal of Physics: Conference Series 176 2009年09月 

  A theoretical assessment of doping α-boron with hydrogen is presented aiming at high Tc superconductor. Dissimilar to other impurities, hydrogen is unique because T site is the most stable site. This position is well suited to the three-center bond. The bottom of conduction band has a large component at this center. Insertion of H atom increases the bonding character of this band through the three-center bond, which is otherwise a weak bond. Enhancement of bonding character of the three-center bond merges the bottom conduction and the top valence bands, yielding a relatively large density of states (DOS) at the Fermi level. This large DOS suggests that H doped α-boron is a promising high Tc material. When the gaseous state H2 is used as the starting material, the formation energy is above 2 eV at the normal condition, so that heavy doping is not easy. High-pressure process can avoid this difficulty. It is predicted that hydrogen is incorporated easily at p > 18 GPa. A thermodynamic investigation has been made for high-pressure doping method when gases are used as the starting materials. © 2009 IOP Publishing Ltd.
• Possibility of imperfections in α-boron

  Haruhiko Dekura, Koun Shirai, Akira Yanase

  Journal of Physics: Conference Series 176 2009年09月 

  Recently, we have shown by density functional theory calculations that α-boron is the most stable phase at low temperature among icosahedron-based boron crystals. This is consistent with low-temperature crystal growth of α-boron. A problem of the calculation is, however, that the conclusion would be changed if defect states for β-boron, which are observed in experiment, were taken into account. This urges us to suspect the perfectness of α-boron crystal. In this paper, we investigate possibility of imperfections of α-boron from the standpoint of crystal stability. Intrinsic defects of vacancy and self-interstitial have been examined. Based on the total energy calculations, we conclude that intrinsic defects are not present at a level above 0.1 at%. © 2009 IOP Publishing Ltd.
• Electronic structure and electrical resistivity of α-boron under high pressure

  Koun Shirai, Haruhiko Dekura, Akira Yanase, Akira Yanase

  Journal of the Physical Society of Japan 78 8 2009年08月 研究論文（学術雑誌） 

  Recently, it has been discovered that the semiconductor α-boron becomes metallic at high pressures and finally undergoes a superconducting transition at 160 GPa, without causing any phase transition. Before the superconducting transition, a step is often observed in the pressure dependence of electrical resistivity in this class of boron crystals, which possess icosahedron-based structures. This step structure used to be thought to occur due to a phase transitions. In the present paper, we show that the step of α-boron at 50 GPa is not due to a phase transition. It is caused by a gradual change in the bonding character from semiconductor to metal. The increase in the metallic character is caused by the shortening of the three-center bond, which is a characteristic feature of icosahedron-based boron crystals. This shortening of the three-center bond enhances the bonding character of the conduction bottom band and finally closes the band gap. However, even far before the gap closing, the shortening has important consequences for the crystal properties of α-boron: for the changes in the deformation of the lattice and in the librational phonon mode at approximately 50 GPa. This change in structure affects the change in band structure, that is, the bottom of the conduction band initially moves from the Γ point toward the Z point until p = 50 GPa and then almost terminates in the middle point. The step in resistivity is a direct consequence of the change in this energy gap. This provides a coherent understanding of the characteristic changes in resistivity, the deformation of the lattice, and the librational mode. © 2009 The Physical Society of Japan.
• Utilization of high pressure for synthesizing superconducting semiconductors: analysis of Ekimov's method

  Koun Shirai, Haruhiko Dekura, Akira Yanase

  PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 246 3 673 - 678 2009年03月 研究論文（学術雑誌） 

  Use of a high-pressure process is proposed for synthesizing highly doped semiconductors. Working on a real example in a recent experiment by Ekimov on B-doped diamond synthesis, a theoretical investigation has been made of an efficient doping method. The underlying principle is simple: stiffer materials are energetically favorable over softer ones under high pressure. Softer impurities are easily dissolved in stiff crystals. In Ekimov's method, the energy required for a B atom to transfer from boron carbide to diamond comes from the energy gain by converting graphite to diamond, in addition to the entropy effect of dissolving the B atom in diamond. On the basis of this analysis, a potential of more than 10 at% of doping, which would improve T-c, by high-pressure processes is suggested. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
• Valence control and metallization of boron by electronic doping

  H. Dekura, K. Shirai, H. Katayama-Yoshida

  PHYSICA B-CONDENSED MATTER 401 702 - 705 2007年12月 研究論文（学術雑誌） 

  Theoretical investigation has been made for the possibility of efficient doping to a boron, aiming at superconducting application. The idea is that application of high pressure makes it easier to dope soft impurities to stiff host crystals. Along with this line of thought, several of the dopants, Na, Ca, C, H and Li, have been examined. For Na, and H as well as Li, this can be achieved at moderated pressures. In terms of the density of states, Li is the best for superconducting purpose. However, H may also have potential to this application. (C) 2007 Elsevier B.V. All rights reserved.
• Valence control of α-rhombohedral boron by electronic doping

  Haruhiko Dekura, Koun Shirai, Hiroshi Katayama-Yoshida, Hiroshi Katayama-Yoshida

  Journal of Physics Condensed Matter 19 2007年09月 

  It was previously predicted that doping Li into semiconducting boron (α-rhombohedral) brought metallic character to the matrix and possibility a high-Tc superconductor. However, experiments show that Li doping of α-rhombohedral boron is difficult. In this paper, the potential for Li doping of boron is re-examined using the ab initio pseudopotential method. Based on the calculated formation enthalpy, an efficient method for doping is proposed. The method utilizes high pressure, such as 10 GPa. Slight changes in the structural parameters for Li insertion are also resolved, which may be useful for the experimental detection of Li in boron. The stability of α-rhombohedral boron at high pressures is also compared to that of Ga-type structure, which has been put forth as a candidate for the high-pressure phase. The present study gives further confirmation of the stability of α-rhombohedral boron at least up to 70GPa. © IOP Publishing Ltd.
• On the elastic softening due to a vacancy in Si

  J. Ishisada, K. Shirai, H. Dekura, H. Katayama-Yoshida

  12TH INTERNATIONAL CONFERENCE ON PHONON SCATTERING IN CONDENSED MATTER (PHONONS 2007) 92 2007年 研究論文（国際会議プロシーディングス） 

  Recently, an elastic softening at low temperatures has been observed in Si by an ultrasonic measurement. By assuming that an intrinsic defect of vacancy causes this softening, which is suggested by the experiment, the effects of monovacancy on the elastic properties have been theoretically studied. The primal concern of this paper is to survey existence of a low-energy excitation, which would be expected commonly for such an abnormal behavior. Although the static ground-state of monovacancy is stiff owing to the strong Jahn-Teller distortion, it is found that a low-energy excitation really exists in the motion of the neighboring Si atoms surrounding the vacancy.
• H atom relaxation in Si

  K. Shirai, H. Dekura, H. Katayama-Yoshida

  12TH INTERNATIONAL CONFERENCE ON PHONON SCATTERING IN CONDENSED MATTER (PHONONS 2007) 92 2007年 研究論文（国際会議プロシーディングス） 

  It is believed that hydrogen in silicon is located at the bond center. But, the hydrogen atom is actually deviated significantly from the bond center dynamically, which is illustrated by the present calculations. The fast relaxation to bending causes a large decay rate of the H vibration.

講演・口頭発表等

• Stable carbon isotope fractionation in Fe-C system from first principles

  Haruhiko DEKURA

  日本地球惑星科学連合2019年大会 2019年05月 ポスター発表
• Ab initio anharmonic lattice dynamics for Fe-bearing lower mantle minerals

  Haruhiko DEKURA

  日本地球惑星科学連合2019年大会 2019年05月
• Effects of iron on the lattice thermal conductivity of lower mantle minerals evaluated by Ab initio anharmonic lattice dynamics simulations  [通常講演]

  出倉 春彦

  日本地球惑星科学連合2018年大会 2018年05月 口頭発表（一般）
• Ab initio lattice thermal conductivity of MgSiO3 post-perovskite  [通常講演]

  出倉 春彦

  日本地球惑星科学連合2018年大会 2018年05月
• First-Principles Investigation of Thermal Transport Property of Earth's Lowermost Mantle  [招待講演]

  出倉 春彦

  SIAM Conference on Parallel Processing for Scientific Computing 2018年03月 口頭発表（招待・特別）
• Ab initio lattice thermal conductivity of MgO using a full solution to the linearized Boltzmann transport equation  [通常講演]

  出倉 春彦

  日本地球惑星科学連合2017年大会 2017年05月 ポスター発表
• Ab initio anharmonic lattice dynamics calculations for Fe-bearing lower mantle minerals  [通常講演]

  出倉 春彦

  日本地球惑星科学連合2017年大会 2017年05月 口頭発表（一般）
• Thermal conductivity of lower mantle minerals from ab initio anharmonic lattice dynamics  [通常講演]

  出倉春彦

  Goldschmidt 2016 2016年06月 ポスター発表
• Thermal conductivity of lower mantle minerals from ab initio anharmonic lattice dynamics  [通常講演]

  出倉春彦

  日本地球惑星科学連合2016年大会 2016年5月23日 2016年05月 ポスター発表
• Electron-phonon contribution to electrical resistivity of hcp Fe  [通常講演]

  出倉春彦

  日本地球惑星科学連合2016年大会 2016年05月 口頭発表（一般）
• Ab initio lattice thermal conductivity  [通常講演]

  出倉春彦

  Special seminar 2016, Institute of solid state physics, Chinese Academiy of science 公開講演，セミナー，チュートリアル，講習，講義等
• Thermal conductivity of lower mantle minerals from ab initio anharmonic lattice dynamic  [通常講演]

  出倉春彦

  2016 International Conference on the Earth's Deep Interior 口頭発表（一般）

MISC

• MgSiO₃ポストペロブスカイト相の状態方程式

  境毅, 出倉春彦, 平尾直久 高圧討論会講演要旨集 54th 261 2013年10月

受賞

• 2015年11月 Outstanding reviewer award in Solid State Communications
   

  受賞者: 出倉 春彦
• 2014年07月 Outstanding reviewer award in Material Science in Semiconductor processing
   

  受賞者: 出倉 春彦
• 2011年09月 Scientist Presentation Award from The GL-GRC Inter-Institutional Science Symposium
   

  受賞者: 出倉 春彦

共同研究・競争的資金等の研究課題

• 核－マントル物質とダイナミクスの理論モデリング

  日本学術振興会：JSPS: 新学術領域研究(研究領域提案型) 核－マントルの相互作用と共進化～統合的地球深部科学の創成～

  研究期間 : 2015年 -2020年03月 

  代表者 : 土屋 卓久
• 地球内核条件下における金属鉄の第一原理電子輸送特性シミュレーション

  日本学術振興会：科学研究費補助金 (若手 (B))

  研究期間 : 2014年04月 -2016年03月 

  代表者 : 出倉 春彦
• 下部マントル鉱物の熱弾性特性及び熱伝導特性に対する鉄固溶効果の解明

  日本学術振興会: JSPS：科学研究費補助金 (基盤(B))

  研究期間 : 2014年 -2016年 

  代表者 : 土屋 卓久

愛媛大学教員活動実績

教育活動(B)

担当授業科目(B01)

• 2013, 後期, 修士, 地球科学高等実験Ⅲ
• 2013, 後期, 学部, 地球物理学実験
• 2013, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅳ
• 2013, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅱ
• 2013, 後期, 修士, 地球科学高等実験Ⅰ
• 2013, 前期, 学部, 情報地球科学演習
• 2013, 後期, 学部, 地球物理学特論
• 2013, 後期, 学部, 地球物理学実験
• 2013, 前期, 学部, 情報地球科学演習
• 2013, 前期, 修士, 地球科学高等実験Ⅴ
• 2013, 前期, 修士, 地球科学高等実験Ⅰ
• 2013, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅲ
• 2013, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅰ
• 2014, 前期, 学部, 新入生セミナーA
• 2014, 前期, 学部, 情報地球科学演習
• 2014, 前期, 修士, 地球科学高等実験Ⅰ
• 2014, 前期, 修士, 地球科学高等実験Ⅱ
• 2014, 前期, 修士, 地球科学高等実験Ⅴ
• 2014, 前期, 修士, 地球科学高等実験Ⅵ
• 2014, 前期, 学部, 情報地球科学演習
• 2014, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅲ
• 2014, 前期, 修士, 地球科学高等実験Ⅲ
• 2014, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅰ
• 2014, 後期, 修士, 地球科学高等実験Ⅳ
• 2014, 後期, 学部, 地球物理学実験
• 2014, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅳ
• 2014, 後期, 学部, 地球物理学特論
• 2014, 後期, 学部, 地球物理学実験
• 2014, 後期, 修士, 地球科学高等実験Ⅲ
• 2014, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅱ
• 2015, 前期, 修士, 地球科学高等実験Ⅰ
• 2015, 前期, 修士, 地球科学高等実験Ⅴ
• 2015, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅰ
• 2015, 前期, 学部, 情報地球科学演習
• 2015, 前期, 修士, 鉱物学特論
• 2015, 前期, 修士, 地球科学高等実験Ⅱ
• 2015, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅲ
• 2015, 前期, 修士, 地球科学高等実験Ⅵ
• 2015, 前期, 学部, 情報地球科学演習
• 2015, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅲ
• 2015, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅰ
• 2015, 前期, 修士, 地球科学高等実験Ⅵ
• 2015, 前期, 修士, 地球科学高等実験Ⅴ
• 2015, 前期, 修士, 地球科学高等実験Ⅱ
• 2015, 前期, 修士, 鉱物学特論
• 2015, 前期, 学部, 情報地球科学演習
• 2015, 前期, 修士, 地球科学高等実験Ⅰ
• 2015, 後期, 学部, 地球物理学実験
• 2015, 後期, 学部, 地球物理学特論
• 2015, 後期, 修士, 地球科学高等実験Ⅲ
• 2015, 後期, 修士, 地球科学高等実験Ⅳ
• 2015, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅱ
• 2015, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅳ
• 2015, 後期, 学部, 地球物理学実験
• 2016, 前期, 学部, 情報地球科学演習
• 2016, 前期, 修士, 地球科学高等実験Ⅰ
• 2016, 前期, 修士, 地球科学高等実験Ⅱ
• 2016, 前期, 修士, 地球科学高等実験Ⅴ
• 2016, 前期, 修士, 地球科学高等実験Ⅵ
• 2016, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅰ
• 2016, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅲ
• 2016, 後期, 学部, 地球物理学実験
• 2016, 後期, 学部, 地球物理学特論
• 2016, 後期, 修士, 鉱物学特論
• 2016, 後期, 修士, 地球科学高等実験Ⅲ
• 2016, 後期, 修士, 地球科学高等実験Ⅳ
• 2016, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅱ
• 2016, 後期, 修士, 地球科学プレゼンテーション特別実習Ⅳ
• 2016, 後期, 学部, 地球物理学実験
• 2019, 前期, 学部, 地球科学実験Ⅰ
• 2019, 前期, 学部, 情報地球科学演習
• 2019, 前期, 修士, 鉱物学特論
• 2019, 前期, 修士, 地球科学高等実験Ⅰ
• 2019, 前期, 修士, 地球科学高等実験Ⅱ
• 2019, 前期, 修士, 地球科学高等実験Ⅴ
• 2019, 前期, 修士, 地球科学高等実験Ⅵ
• 2019, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅰ
• 2019, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅲ
• 2019, 前期, 修士, 地球科学プレゼンテーション特別実習Ⅱ
• 2019, 前期, 修士, 地球科学高等実験Ⅲ
• 2019, 前期, 学部, 情報地球科学演習