Faculty Profiles - TSURUTA Kenji

Papers - TSURUTA Kenji

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Design of multiple-resonant phononic metasurface for sound absorbing and energy harvesting devices

Akira Kojima, Julien Cuau, Yuri Fukaya, Kenji TSURUTA

Japanese Journal of Applied Physics 2025.3

Photoinduced dynamics during electronic transfer from narrow to wide bandgap layers in one-dimensional heterostructured materials Reviewed

Yuri Saida, Thomas Gauthier, Hiroo Suzuki, Satoshi Ohmura, Ryo Shikata, Yui Iwasaki, Godai Noyama, Misaki Kishibuchi, Yuichiro Tanaka, Wataru Yajima, Nicolas Godin, Gaël Privault, Tomoharu Tokunaga, Shota Ono, Shin-ya Koshihara, Kenji Tsuruta, Yasuhiko Hayashi, Roman Bertoni, Masaki Hada

Nature Communications 15 ( 1 ) 2024.5

Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

Electron transfer is a fundamental energy conversion process widely present in synthetic, industrial, and natural systems. Understanding the electron transfer process is important to exploit the uniqueness of the low-dimensional van der Waals (vdW) heterostructures because interlayer electron transfer produces the function of this class of material. Here, we show the occurrence of an electron transfer process in one-dimensional layer-stacking of carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs). This observation makes use of femtosecond broadband optical spectroscopy, ultrafast time-resolved electron diffraction, and first-principles theoretical calculations. These results reveal that near-ultraviolet photoexcitation induces an electron transfer from the conduction bands of CNT to BNNT layers via electronic decay channels. This physical process subsequently generates radial phonons in the one-dimensional vdW heterostructure material. The gathered insights unveil the fundamentals physics of interfacial interactions in low dimensional vdW heterostructures and their photoinduced dynamics, pushing their limits for photoactive multifunctional applications.

DOI： 10.1038/s41467-024-48880-3

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Other Link： https://www.nature.com/articles/s41467-024-48880-3

Valley Pseudospin Polarized Evanescent Coupling between Microwave Ring Resonator and Waveguide in Phononic Topological Insulators Reviewed

Daiki Hatanaka, Hiroaki Takeshita, Motoki Kataoka, Hajime Okamoto, Kenji Tsuruta, Hiroshi Yamaguchi

Nano Letters 24 ( 18 ) 5570 - 5577 2024.5

Publishing type：Research paper (scientific journal)

A coupled ring-waveguide structure is at the core of bosonic wave-based information processing systems, enabling advanced wave manipulations such as filtering, routing, and multiplexing. However, its miniaturization is challenging due to momentum conservation issues in rings with larger curvature that induce significant backscattering and radiation leakage and hampering stable operation. Here, we address it by taking an alternative approach of using topological technology in wavelength-scale and microwave ring-waveguide coupled systems built in nanoengineered phononic crystals. Our approach, which leverages pseudospin conservation in valley topological systems, eliminates phonon backscattering and achieves directional evanescent coupling. The resultant hypersonic waves in the tiny ring exhibit robust transport and resonant circulation. Furthermore, the ring-waveguide hybridization enables critical coupling, where valley-dependent ring-waveguide interference blocks the transmission. Our findings reveal the capability of topological phenomena for managing ultrahigh-frequency phonons in nano/microscale structures and pave the way for advanced phononic circuits in classical and quantum signal processing applications.

DOI： 10.1021/acs.nanolett.4c00806

Scopus

PubMed

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Robust and Reconfigurable Waveguide Design in Valley-Topological Phononic Crystals Reviewed

Md. Shuzon Ali, Yusuke Hata, Motoki Kataoka, Masaaki Misawa, Kenji Tsuruta

Materials Science Forum 1107 141 - 145 2023.12

Authorship：Corresponding author Publishing type：Research paper (scientific journal) Publisher：Trans Tech Publications, Ltd.

As an analogy of topological insulators and superconductors, “topological phononics”, which applies the concept of band topology to acoustic dispersion, has attracted increasing attention in recent years. We present design of topological acoustic/elastic waveguides in phononic crystals. Topological waveguides are designed from the phonon dispersion analyses by finding edge modes appearing at interfaces between phononic crystals with different band topologies. As a prototype model, we first designed the topological waveguides in kHz regimes. Experimental validation of the designed waveguide has been performed in the frequency region via laser-doppler measurements. The robustness of the waveguide propagation against defects, corners, and structural inaccuracy in the waveguide has been quantitatively evaluated. We also introduced a structural transition of local symmetry inversion in the phononic crystal to implement a reconfigurability into the waveguide .Further development toward GHz regime will pave the way to the development of next-generation information devices using the proposed structures as an alternative or complimentary approach.

DOI： 10.4028/p-jt9zkn

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Active control of localized mode and transmission in topological phononic waveguides by non-Hermitian modulation Reviewed

Md. Shuzon Ali, Yusuke Hata, Kenji Tsuruta

Applied Physics Express 16 ( 9 ) 2023.9

Reconfigurable waveguide based on valley topological phononic crystals with local symmetry inversion via continuous translation Reviewed

Md. Shuzon Ali, Motoki Kataoka, Masaaki Misawa, Kenji Tsuruta

Japanese Journal of Applied Physics 62 ( SJ ) SJ1002 - SJ1002 2023.7

Authorship：Corresponding author Publishing type：Research paper (scientific journal) Publisher：IOP Publishing

Abstract

We proposed a reconfigurable valley topological acoustic waveguide constructed using a 2D phononic crystal (PnC) with C_3v symmetric arrangement of three rods in the unit cell. An interface between two types of PnCs with differently oriented unit cells exhibits high robustness of the valley transport of acoustic waves via the topologically protected state. Structural reconfiguration was introduced by the continuous translation of rod arrays in the PnCs. The topological phase transition in this translational change was quantitatively identified by the change in the Berry curvature. The translation of the rods leaves a dimer array at the interface, creating a localized/defective mode along the waveguide. Despite the presence of the localized mode, the acoustic wave can propagate along the reconfigurable waveguide the same as the original waveguide. The continuous translation of a rod array can be used to turn on and off the bandgap. This can be a new approach to design a robust acoustic device with a high reconfigurability.

DOI： 10.35848/1347-4065/acae63

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Other Link： https://iopscience.iop.org/article/10.35848/1347-4065/acae63/pdf

Acoustic metasurfaces and topological phononics for acoustic/elastic device design Invited Reviewed

Kenji Tsuruta

Japanese Journal of Applied Physics 62 ( SJ ) 2023.7

Intermediate State between MoSe₂ and Janus MoSeS during Atomic Substitution Process Reviewed

Hiroo Suzuki, Yijun Liu, Masaaki Misawa, Chiyu Nakano, Yingzhe Wang, Ryo Nakano, Kentaro Ishimura, Kenji Tsuruta, Yasuhiko Hayashi

Nano Letters 2023.5

Self-Limiting Growth of Monolayer Tungsten Disulfide Nanoribbons on Tungsten Oxide Nanowires Reviewed

Hiroo Suzuki, Misaki Kishibuchi, Masaaki Misawa, Kazuma Shimogami, Soya Ochiai, Takahiro Kokura, Yijun Liu, Ryoki Hashimoto, Zheng Liu, Kenji Tsuruta, Yasumitsu Miyata, Yasuhiko Hayashi

ACS Nano 2023.5

Tracking Optical Properties During Atomic Substitution Process from MoSe2 to Janus MoSeS

Hiroo Suzuki, Masaaki Misawa, Yingzhe Wang, Kenji Tsuruta, Yasuhiko Hayashi

JSAP-Optica Joint Symposia 2023 Abstracts 32 20p_A602_5 - 20p_A602_5 2023

Publishing type：Research paper (international conference proceedings) Publisher：Optica Publishing Group

Janus transition metal dichloride (TMDC) is a TMDC with two different chalcogenide elements on the upper and lower surfaces. This special structure is reported to break the out-of-plane symmetry of the monolayer TMDC and produce out-of-plane polarization. This is expected to lead to the development of new electronic properties, such as Rashba spin splitting and piezoelectricity. There have been several reports on the synthesis of Janus TMDCs, and in recent years, the use of chalcogen spices containing H₂ plasma for atomic substitution on the surface of TMDC has attracted attention since Janus TMDCs can be generated at room temperature [1,2]. However, the generation process of Janus TMDCs with this method has not been well under-stood. In addition, the physical properties in the intermediate state between TMDC and Janus TMDC have also not been clarified, although the control of the intermediate state is important for tuning the physical properties of Janus TMDCs. Thus, elucidating the intermediate partially sub-stituted Janus (PSJ) state between MoSe₂ and Janus MoSeS state is essential for understanding the synthesis dynamics and tuning the electrical properties of TMDCs.

DOI： 10.1364/jsapo.2023.20p_a602_5

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Design and Robustness Evaluation of Valley Topological Elastic Wave Propagation in a Thin Plate with Phononic Structure Reviewed

Motoki Kataoka, Masaaki Misawa, Kenji Tsuruta

Symmetry 14 ( 10 ) 2022.10

Authorship：Corresponding author Publishing type：Research paper (scientific journal)

Based on the concept of band topology in phonon dispersion, we designed a topological phononic crystal in a thin plate for developing an efficient elastic waveguide. Despite that various topological phononic structures have been actively proposed, a quantitative design strategy of the phononic band and its robustness assessment in an elastic regime are still missing, hampering the realization of topological acoustic devices. We adopted a snowflake-like structure for the crystal unit cell and determined the optimal structure that exhibited the topological phase transition of the planar phononic crystal by changing the unit cell structure. The bandgap width could be adjusted by varying the length of the snow-side branch, and a topological phase transition occurred in the unit cell structure with threefold rotational symmetry. Elastic waveguides based on edge modes appearing at interfaces between crystals with different band topologies were designed, and their transmission efficiencies were evaluated numerically and experimentally. The results demonstrate the robustness of the elastic wave propagation in thin plates. Moreover, we experimentally estimated the backscattering length, which measures the robustness of the topologically protected propagating states against structural inhomogeneities. The results quantitatively indicated that degradation of the immunization against the backscattering occurs predominantly at the corners in the waveguides, indicating that the edge mode observed is a relatively weak topological state.

DOI： 10.3390/sym14102133

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First-principles analysis of stearic acid adsorption on calcite (104) surface Reviewed

Narumi Machida, Masaaki Misawa, Yuki Kezuka, Kenji Tsuruta

e-Journal of Surface Science and Nanotechnology 20 ( 4 ) 261 - 265 2022.8

Surface Diffusion-Limited Growth of Large and High-Quality Monolayer Transition Metal Dichalcogenides in Confined Space of Microreactor. Reviewed International journal

Hiroo Suzuki, Ryoki Hashimoto, Masaaki Misawa, Yijun Liu, Misaki Kishibuchi, Kentaro Ishimura, Kenji Tsuruta, Yasumitsu Miyata, Yasuhiko Hayashi

ACS nano 2022.7

Language：English Publishing type：Research paper (scientific journal)

Transition metal dichalcogenides (TMDCs), including MoS2 and WS2, are potential candidates for next-generation semiconducting materials owing to their atomically thin structure and strong optoelectrical responses, which allow for flexible optoelectronic applications. Monolayer TMDCs have been grown utilizing chemical vapor deposition (CVD) techniques. Enhancing the domain size with high crystallinity and forming heterostructures are important topics for practical applications. In this study, the size of monolayer WS2 increased via the vapor-liquid-solid growth-based CVD technique utilizing the confined space of the substrate-stacked microreactor. The use of spin-coated metal salts (Na2WO4 and Na2MoO4) and organosulfur vapor allowed us to precisely control the source supply and investigate the growth in a systematic manner. We obtained a relatively low activation energy for growth (1.02 eV), which is consistent with the surface diffusion-limited growth regime observed in the confined space. Through systematic photoluminescence (PL) analysis, we determined that a growth temperature of ∼820 °C is optimal for producing high-quality WS2 with a narrow PL peak width (∼35 meV). By controlling the source balance of W and S, we obtained large-sized fully monolayered WS2 (∼560 μm) and monolayer WS2 with bilayer spots (∼1100 μm). Combining two distinct sources of transition metals, WS2/MoS2 lateral heterostructures were successfully created. In electrical transport measurements, the monolayer WS2 grown under optimal conditions has a high on-current (∼70 μA/μm), on/off ratio (∼5 × 108), and a field-effect mobility of ∼7 cm2/(V s). The field-effect transistor displayed an intrinsic photoresponse with wavelength selectivity that originated from the photoexcited carriers.

DOI： 10.1021/acsnano.2c05076

PubMed

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Numerical and experimental analysis of additively manufactured particle dampers at low frequencies Reviewed

Honghu Guo, Kazuo Ichikawa, Hiroyuki Sakai, Heng Zhang, Xiaopeng Zhang, Kenji Tsuruta, Kanjuro Makihara, Akihiro Takezawa

Powder Technology 396 696 - 709 2022.1

Publishing type：Research paper (scientific journal)

Particle damping is an effective method for increasing structural damping and is utilized in many fields. Using laser powder bed fusion (LPBF) additive manufacturing (AM), a new integrated particle damper can be produced by deliberately leaving unfused powder inside the structure. This study focuses on experimentally and numerically investigating the damping mechanism and performance of additively manufactured particle dampers in the low-frequency range (< 100 Hz). A numerical simulation approach based on the discrete element method was developed to predict the damping performance of a particle damper. To reduce the computational cost, a multi-unit particle damper (MUPD) was introduced. A series of particle dampers of 316 L stainless steel with different numbers and sizes of unit cells were built using LPBF. The damping mechanism and performance of additively manufactured MUPDs (AM-MUPD) were studied, the results cross-verified via experiments and simulations, and the effects of unit cell size and number investigated.

DOI： 10.1016/j.powtec.2021.11.029

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Design of High-efficiency Sound Absorption and Energy Harvesting Devices Using Acoustic Metasurfaces Reviewed

R. Takami, M. Misawa, and K. Tsuruta

Proceedings of Symposium on Ultrasonic Electronics (USE2021) 42 3Pb4-7 2021.10

Design of topological phononic structure for multimode propagation Reviewed

H. Takeshita, M. Misawa, and K. Tsuruta

Proceedings of Symposium on Ultrasonic Electronics (USE2021) 42 3Pb1-2 2021.10

Band Structure Design for a Two-Dimensional Phononic Crystal using Various Optimization Methods Reviewed

K. Akae, M. Misawa, and K. Tsuruta

Proceedings of Symposium on Ultrasonic Electronics (USE2021) 42 2Pa1-3 2021.10

Design and measurement of topological elastic waveguide based on phononic crystal Reviewed

M. Kataoka, M. Misawa, and K. Tsuruta

Proceedings of Symposium on Ultrasonic Electronics (USE2021) 42 1J1-1 2021.10

Photoinduced oxygen transport in cobalt double-perovskite crystal EuBaCo2O5.39 Reviewed

Masaki Hada, Satoshi Ohmura, Tadahiko Ishikawa, Masaki Saigo, Naoya Keio, Wataru Yajima, Tatsuya Suzuki, Daisuke Urushihara, Kou Takubo, Yusuke Masaki, Makoto Kuwahara, Kenji Tsuruta, Yasuhiko Hayashi, Jiro Matsuo, Takayoshi Yokoya, Ken Onda, Fuyuki Shimojo, Muneaki Hase, Sumio Ishihara, Toru Asaka, Nobuyuki Abe, Taka-hisa Arima, Shin-ya Koshihara, Yoichi Okimoto

Applied Materials Today 24 101167 - 101167 2021.9

Low-frequency sound absorbing metasurface using multilayer split resonators Reviewed

Shota Takasugi, Keita Watanabe, Masaaki Misawa, Kenji Tsuruta

Japanese Journal of Applied Physics 60 ( {SD} ) 2021.7

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Papers - TSURUTA Kenji