Faculty Profiles - TSURUTA Kenji

1502 Ab Initio Simulation for Structure and Optical Response of Gemini-HBC

Shimizu Tatsuki, Tsuruta Kenji, Fukano Hideki

The Computational Mechanics Conference 2011 ( 24 ) 471 - 473 2011.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

A graphite nanotube is composed of Gemini type hexabenzocoronene (Gemini-HBC) as the hole-transport layer and the fullerene as the electron-transport layer. We study the doping effect on the electronic properties of Gemini-HBC to make the absorption peak broader, expecting to cover an unharvested energy resource. Here we assume that structure of doped Gemini-HBC is well represented by substituting dopant atom to one of carbon sites. Calculations of the energy and absorption spectrum are performed by the ab-initio computational method. As a result, the absorption peak of the Gemini-HBC is about 0.5μm, whereas the first and second peaks for doped Gemini-HBC are also approximately 0.5μm. In addition, the absorption spectrum of F-doped Gemini-HBC has an additional peak around 0.95μm, implying the sunlight with the longer wavelength may be absorbed.

1508 Diffusion barrier of Li in carbon-based anode material in Li-ion secondary battery via ab-initio and hybrid quantum/classical molecular-dynamics method

INAGAKI Yosuke, TSURUTA Kenji

The Computational Mechanics Conference 2011 ( 24 ) 485 - 486 2011.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Lithium ion battery (LiB) is widely used in portable electronic devices, such as cellular phones and laptop computers. Recently, needs for higher efficiency of the battery has been increasing rapidly due to the demand for electric and hybrid electric vehicle. At present, anode of LiB is mainly made of graphite. Recently, graphene has been attracting more attention as an alternative anode material. The effect of impurity doping to graphene has also been investigated recently. To optimize the materials combination for the anode applications microscopic mechanisms of such enhancement of electric capacity in LiB have to be identified. Using an ab-initio computational method, based on the density-functional theory, and its hybridized method with the classical molecular dynamics, we investigate dynamical behavior, such as diffusion processes, of Li atom in the carbon based materials with pristine, defected, and doped graphene.

1503 Large Scale Molecular Dynamics Analysis on Vacancy Interaction in Si Crystal

TAKATA Kazuaki, TSURUTA Kenji

The Computational Mechanics Conference 2011 ( 24 ) 474 - 475 2011.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Vacancy interaction in Si crystal is studied by molecular-dynamics simulations. Using tight-binding molecular dynamics and classical molecular dynamics methods, we calculate an effective interaction potential of Si vacancy pair in bulk and in a thin slab at several temperatures. In the case of vacancy pair in bulk crystal, results reveal that there is an effective "capture radius" of the vacancies at around 8 Åat 300K and 13 Å at 600K and 1000K. Stable structure and electronic states around the vacancies in Si slab near the surface are qualitatively different from their bulk properties, reflecting a proximity surface electronic state. Results of diffusion behavior and interaction potential of the vacancy pair in the slab at finite temperatures are also reported.

22aGQ-10 Molecular Dynamics Analysis on Vacancy Interaction near Surface and Interface in Si Crystal

Takata K., Tsuruta K., Ogawa T., Iyetomi H.

Meeting abstracts of the Physical Society of Japan 66 ( 2 ) 981 - 981 2011.8

27pTJ-10 Analyses on spin-orbit coupling effects of a silicon single vacancy via DFT calculations

Ogawa Takafumi, Tsuruta Kenji, Iyetomi Hiroshi, Nemoto Yuichi, Yamada-Kaneta Hiroshi, Goto Terutaka

Meeting abstracts of the Physical Society of Japan 66 ( 1 ) 979 - 979 2011.3

フォノニック結晶による超音波の音響レンズ効果とエネルギー輸送効率

菅野祐輔, 笠井祐樹, 鶴田健二, 藤森和博, 深野秀樹, 野木茂次

日本機械学会計算力学講演会論文集(CD-ROM) 24th 2011

半導体結晶表面における弾性波伝搬の大規模分子動力学シミュレーション

藥師川裕貴, 鶴田健二, 藤森和博

日本機械学会計算力学講演会論文集(CD-ROM) 24th 2011

26aWZ-12 Analyses localized electron orbitals around a silicon single vacallcy via DFT calculations

Ogawa Takafumi, Tsuruta Kenji, Iyetomi Hiroshi, Nemoto Yuichi, Yamada-Kaneta Hiroshi, Goto Terutaka

Meeting abstracts of the Physical Society of Japan 65 ( 2 ) 928 - 928 2010.8

20aHT-10 Multiscale Analysis on Impurity Segregation to Dislocation in Alumina

Tsuruta K., Koyama T., Ogata S., Hyodo S.

Meeting abstracts of the Physical Society of Japan 65 ( 1 ) 971 - 971 2010.3

Parallel FDTD simulations on optical and acoustic metamaterials

Kenji Tsuruta, Shinji Nagai, Ryosuke Umeda, Tomoyuki Kurose, Noriaki Maetani

Materials Research Society Symposium Proceedings 1223 1223-EE06 2010

Ab Initio Simulation for Structure and Optical Response of Gemini-HBC

Tatsuki Shimizu, Kenji Tsuruta

447 - 450 2010

108 Hybrid Quantum/Classical Molecular-Dynamics Study on Dislocation Motion and Nanodopant Effects in Alumina

TSURUTA Kenji, HAYASHI Akihiro, KOYAMA Toshiyuki, OGATA Shuji, HYODO Shiaki

The Computational Mechanics Conference 2009 ( 22 ) 390 - 391 2009.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

We perform molecular-dynamics simulations to investigate the atomic and electronic structures of a basal edge dislocation in α-Al_2O_3. Inter-core interactions between a dissociated partial pair are evaluated by a million-atom classical molecular dynamics. The interactions consists of a short-ranged repulsion due to the elastic interaction between two singular points and a long-ranged attraction due to the stacking-fault formed between the two partials. The atomic rearrangements in the full and in the partial dislocation cores are analyzed by a hybrid quantum/classical molecular dynamics method. The local electronic structure in the dislocation core is evaluated by the density-functional method applied for a quantum-cluster region in the hybrid simulation. Effects of a doped Si atom segregated to the dislocation core are also analyzed.

1701 An FDTD Analysis of Light Confined Structure by Electromagnetic Metamaterials

NAGAI Shinji, TSURUTA Kenji, TOTSUJI Chieko

The Computational Mechanics Conference 2009 ( 22 ) 452 - 453 2009.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Using the two dimensional Finite Difference Time Domain method, we demonstrate a light-confinement phenomenon by a structure composed of a negative-refractive-indexed (NRI) material. The structure, consisting of triangular lattice of mediums with a NRI and a normal material, is designed to confine an incident light by peculiar refractions at the materials boundaries. To model realistically the NRI material, we introduce the Drude-Lorentz model for the dielectric response at optical frequencies. The effects of dielectric loss in the NRI medium on the confinement efficiency of the proposed structure is reported.

1706 Numerical Simulation of Acoustic Wave in a Two-Dimensional Phononic Crystal : Negative Refraction and Lens Effect

MAETANI Noriaki, TSURUTA Kenji, TOTSUJI Chieko

The Computational Mechanics Conference 2009 ( 22 ) 462 - 463 2009.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Lens effect of acoustic waves in a two-dimensional (2D) phononic crystal is studied by numerical simulation based on the finite-difference time-domain (FDTD) method. We calculate the phonon band structure of 2D phononic crystals, consisting of metal cylinders placed periodically in water. Lens effect is observed by the negative refraction of acoustic waves, which results in acoustic waves refocused at the point outside the crystal. To increase the focal intensity, we introduce a 2D phononic crystal shield with a different composition of material, which reflects incident acoustic waves from the source. We show how the focal intensity is improved by using the 2D phononic crystal shield.