Article
Materials Science, Multidisciplinary
Mengzhou Liao, Paolo Nicolini, Tomas Polcar
Summary: Layered materials, such as MoS2, graphite, h-BN, and mica, have complex origins of friction on their surfaces. A new method combining a two-dimensional friction force microscope technology and a two-dimensional friction model can separate anisotropic and isotropic friction forces on these atomically flat surfaces. The study reveals the existence of elemental hopping combinations and the isotropic component in total friction, providing insights into the properties of individual friction components and potential applications of solid lubricants.
Article
Materials Science, Multidisciplinary
Christian Northe, Giandomenico Palumbo, Jonathan Sturm, Christian Tutschku, M. Ewelina Hankiewicz
Summary: In this study, the role of quantum geometry in ideal Chern insulators is analyzed to describe transport in the presence of external magnetic and electric fields. Novel Berry connections and the deformation of quantum geometry are observed, and the conditions for specific algebra realization are discussed. The effect of the new quantum geometry on electrical transport is investigated, with measurable quantum-mechanical corrections in the Hall response.
Article
Green & Sustainable Science & Technology
Yunshuo Wang, Yuxue Zhang, Hideo Kimura, Jinqi Wang, Chuanxin Hou, Xiubo Xie, Xueqin Sun, Yuping Zhang, Wei Du, Xiaoyang Yang
Summary: A simple chemical intercalation process combined with melamine-assisted expansion strategy is used to prepare nitrogen-doping expanded graphite (N-EG) with a worm-like structure from waste graphite as an ideal lithium-oxygen (Li-O2) battery cathode. The N-EG demonstrates excellent electrochemical performances, including high specific capacity, excellent rate performance, and long cycle stability, making it a promising candidate for Li-O2 batteries.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Chemistry, Physical
F. Nilsson, M. Kuisma, S. Pakdel, K. S. Thygesen
Summary: We explore a new platform for realizing excitonic insulators by studying van der Waals bilayers made of two-dimensional Janus materials. Unlike previous studies, our research shows that these Janus bilayers are intrinsic excitonic insulators. Through ab initio calculations, we obtain the quasiparticle band structures, screened Coulomb interaction, and interlayer exciton binding energies of the bilayers. Using these calculations, we construct a BCS-like Hamiltonian of the exciton condensate and solve the mean-field gap equation to identify 16 vdW Janus bilayers with insulating ground states and superfluid properties. Our findings reveal a new class of advanced materials that may exhibit novel excitonic phases at low temperatures, highlighting the delicate competition between interlayer hybridization, spin-orbit coupling, and dielectric screening that governs their properties.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Mathematics
Giacomo Canevari, Antonio Segatti
Summary: In this paper, the gradient flow of the Ginzburg-Landau energy is considered, which generates singular points (vortices) in vector fields on Riemannian manifolds. It is rigorously proved that the dynamics of vortices follow the gradient flow of the renormalized energy.
JOURNAL OF FUNCTIONAL ANALYSIS
(2023)
Article
Materials Science, Multidisciplinary
R. Rodriguez-Quintana, G. Carbajal-Franco, H. Rojas-Chavez
Summary: This study investigated the adsorption of H-2 on graphite surfaces with and without the presence of nickel. The addition of nickel on the graphite surface was found to enhance the adsorption of H-2 molecules, with the removal of nickel occurring when more than two H-2 molecules were adsorbed.
Article
Materials Science, Multidisciplinary
Danni Chen, Jing Ning, Dong Wang, Boyu Wang, Jianglin Zhao, Jincheng Zhang, Yue Hao
Summary: GaN on graphene/Al2O3 substrates compensates for the defects caused by MOCVD on mismatched substrates. An intermediate layer of AlN or ZnO nanowalls is needed to provide sufficient nucleation sites on graphene without dangling bonds. High-quality GaN crystals with low compressive stress and dislocation density were successfully synthesized on nitrogen-doped graphene by MOCVD. The improved adsorption energy of Ga atom on nitrogen-doped graphene and atomic nitrogen pretreatment on monolayer graphene contribute to the nucleation of GaN films.
SCIENCE CHINA-MATERIALS
(2023)
Article
Biochemistry & Molecular Biology
Lidia Magerusan, Florina Pogacean, Stela Pruneanu
Summary: Due to the safety concerns associated with acetaminophen, a quick and environmentally friendly method using direct voltage application in saltwater has been developed to synthesize nitrogen-doped graphene (exf-NGr). The exf-NGr-modified electrode shows excellent performance in acetaminophen detection and quantification, with good reproducibility and stability, as well as wide detection range capabilities.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Health Care Sciences & Services
Alexander J. Nedopil, Stephen M. Howell, Maury L. Hull
Summary: This study evaluated the effects of different levels of congruency in knee arthroplasty inserts. The results showed that adding congruency to the lateral articular surface limits tibial orientation and overtightens the posterior cruciate ligament. These effects can adversely affect the motion and stability of the knee joint.
JOURNAL OF PERSONALIZED MEDICINE
(2022)
Article
Chemistry, Physical
Chunlei Chi, Zheng Liu, Guanwen Wang, Bin Qi, Zhipeng Qiu, Yingchun Yan, Chao Huangfu, Xiaolong Lu, Xinhou Yang, Min Gong, Ke Cao, Tong Wei, Zhuangjun Fan
Summary: This study proposes a new quasi-graphite structure anode material with abundant edge-nitrogen doping, micropores structure, and enhanced graphite nanodomains for potassium ion batteries. The material exhibits high intercalation capacity at low potentials, outstanding rate performance, and long-term cycle stability. The construction of quasi-graphite with heteroatom doping is proven to be feasible for large ion storage.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Dongfeng Sun, Li Li, Yuan Yu, Luo Huang, Fangyou Meng, Qingmei Su, Shufang Ma, Bingshe Xu
Summary: The co-doped graphite carbon nitride catalyst with B atoms and cyano groups exhibited excellent photocatalytic nitrogen fixation performance and stability, attributed to the nitrogen vacancies created by the dopants that enhanced the electron transfer rate and separation efficiency. The nitrogen photofixation rate of the catalyst was significantly higher than that of pure carbon nitride, and the NH4+ generation rate remained stable even after multiple cycles, showcasing its potential for sustainable nitrogen conversion applications.
JOURNAL OF COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Physical
Carlos Ayestaran Latorre, James P. Ewen, Daniele Dini, M. C. Righi
Summary: Diamond and diamond-like carbon coatings are widely used in various fields, and the hydrophilicity of these surfaces is crucial for their biocompatibility and tribological performance in aqueous environments. Different dopants such as B, N, and O have been studied for their effects on carbon film hydrophilicity, with results showing enhancement of hydrophilicity through different mechanisms, notably through spontaneous chemisorption and increased interaction in H-bond networks by B dopants.
Article
Materials Science, Ceramics
Jing Zhang, Yuchang Su, Hongzhi Zhang, Zhongbao Luo, Qiushan Yu
Summary: In this study, carbon/nitrogen-doped graphite (Co/NC) composites were fabricated as efficient microwave-absorbing materials by combining carbon materials with magnetic metals. The Co/NC-800 composite showed excellent microwave-absorbing performance with strong absorption, broad effective absorption bandwidth, and lighter weight, due to optimal impedance matching, multiple scattering, and strong dielectric loss. The research may serve as a guideline for the fabrication of other light carbon-based magnetic metal composites for EM wave absorption.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Zongyao Zhang, Zhihong Gao, Yanqi Zhang, Zaoxue Yan, Isaac Kesse, Wei Wei, Xinhong Zhao, Jimin Xie
Summary: Hierarchical porous nitrogen-doped graphite from tissue paper (N-ATG) shows excellent performance as a symmetric supercapacitor electrode material, with ultra-high capacitance and energy densities suitable for high power density operations. Its key features include high specific surface area, large pore diameter, high nitrogen doping content, graphitized structure with widened lattice distance, dense defects and high packing density, which contribute to its outstanding performance.
JOURNAL OF POWER SOURCES
(2021)
Article
Physics, Mathematical
Seonwoo Kim, Insuk Seo
Summary: In this article, the energy landscapes and metastable behavior of Ising and Potts models on two-dimensional square or hexagonal lattices in the low-temperature regime are investigated. The study focuses on the absence of an external magnetic field in these models, revealing a large and complex saddle structure between ground states. By analyzing the saddle structures and temperature thresholds, the conditions for metastable states and Eyring-Kramers formula are rigorously established, providing insights into transitions between ground states and the energy landscape.
COMMUNICATIONS IN MATHEMATICAL PHYSICS
(2022)
Article
Physics, Applied
Hui Zhang, Mina Maruyama, Yanlin Gao, Susumu Okada
Summary: The electronic structure of covalent networks of triangular graphene flakes embedded in hexagonal boron nitride depends on the arrangements of the flakes and border atom species. Heterostructures comprising a copolymer of triangular graphene flakes exhibit flat dispersion bands near the Fermi level. A heterostructure made of [3]triangulene is a semiconductor with a moderate direct gap of 0.7 eV and flat band nature throughout the Brillouin zone, attributed to the hybridization between non-bonding states of the triangulene and p(z) orbitals of border B and N atoms.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
Yanlin Gao, Haruna Nakajima, Mina Maruyama, Takashi Taniguchi, Kenji Watanabe, Ryo Kitaura, Susumu Okada
Summary: We investigated the energetics and electronic structure of monolayer MoS2 with periodic structural corrugations using density functional theory. The corrugated MoS2 sheet showed a slight increase in total energy with increasing corrugation height, indicating the presence of intrinsic and extrinsic nanometer-scale structural corrugations. The corrugation induced shifts in the valence and conduction band edges due to local strain at the wrinkle peak. By injecting holes through an external electric field, the corrugated MoS2 sheet exhibited a one-dimensional conducting channel. This suggests that corrugation can be used to control the dimensionality of electrons and holes in two-dimensional materials without implementing one-dimensional boundary conditions.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Shuhong Li, Tomonori Nishimura, Mina Maruyama, Susumu Okada, Kosuke Nagashio
Summary: The adsorbed oxygen on the surface of MoS2 assists in sulfur vacancy formation, causing defects in the material. At high temperatures, the sulfur atoms dissociate from MoS2 with the help of adsorbed oxygen, while at even higher temperatures, direct sulfur desorption dominates. A preannealing treatment effectively removes adsorbed oxygen and prevents defect formation.
NANOSCALE ADVANCES
(2023)
Article
Physics, Applied
Nadia Sultana, Mina Maruyama, Yanlin Gao, Susumu Okada
Summary: Based on density functional theory (DFT), the electronic structure of multilayer graphene under perpendicular electric field was investigated. DFT calculations showed that the number of layers and stacking arrangement have a significant impact on the electronic structure of multilayer graphene under perpendicular electric field. Multilayer graphene with AB stacking exhibits metallic or semi-metallic properties based on the odd or even number of layers when an electric field is applied. Multilayer graphene with ABC stacking is a semiconductor with a flat band at the valence- and conduction-band edges under electric field, regardless of the number of layers. The electronic structure near the Fermi level of multilayer graphene with AA stacking is insensitive to the external electric field.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Biochemistry & Molecular Biology
Xiaoni Zhang, Miwa Hikichi, Takushi Iimori, Yuki Tsujikawa, Mei Yuan, Masafumi Horio, Kunio Yubuta, Fumio Komori, Masahiro Miyauchi, Takahiro Kondo, Iwao Matsuda
Summary: We propose an improved method for synthesizing borophane sheets. By incorporating hydrochloric acid into the ion-exchange reaction, we significantly increased the production yield from 20% to over 50%. Through a thorough examination, we gained insights into the underlying mechanisms and discovered that hydrochloric acid accelerates borophene production and isolates high-purity products. This method has the potential to enable the production of novel topological 2D materials with potential industrial applications.
Article
Biochemistry & Molecular Biology
Norinobu Watanabe, Keisuke Miyazaki, Masayuki Toyoda, Kotaro Takeyasu, Naohito Tsujii, Haruki Kusaka, Akiyasu Yamamoto, Susumu Saito, Masashi Miyakawa, Takashi Taniguchi, Takashi Aizawa, Takao Mori, Masahiro Miyauchi, Takahiro Kondo
Summary: Researchers synthesized r-BS and evaluated its performance as a semiconductor by measuring the Seebeck coefficient and photo-electrochemical responses. The results indicate that r-BS is a p-type semiconductor. A distinct Fano resonance was observed in Fourier transform infrared absorption spectroscopy, suggesting intrinsic doping of p-type carriers in r-BS. These findings demonstrate the potential application prospects of r-BS.
Article
Chemistry, Multidisciplinary
Katsuaki Sugawara, Haruki Kusaka, Tappei Kawakami, Koki Yanagizawa, Asuka Honma, Seigo Souma, Kosuke Nakayama, Masashi Miyakawa, Takashi Taniguchi, Miho Kitamura, Koji Horiba, Hiroshi Kumigashira, Takashi Takahashi, Shin-ichi Orimo, Masayuki Toyoda, Susumu Saito, Takahiro Kondo, Takafumi Sato
Summary: Boron-based two-dimensional materials, especially rhombohedral boron monosulfide (r-BS), with its unique layered crystal structure, are being extensively studied for their potential applications in nanoelectronics. However, the analysis of the fundamental electronic properties of r-BS has been limited due to the lack of available large crystals. In this study, we utilize microfocused angle-resolved photoemission spectroscopy (micro-ARPES) to directly map the band structure of a tiny r-BS powder crystal, revealing that r-BS is a p-type semiconductor with an anisotropic in-plane effective mass and a band gap larger than 0.5 eV. These findings demonstrate the high applicability of micro-ARPES for investigating small powder crystals and provide new insights into the unexplored electronic states of novel materials.
Article
Chemistry, Physical
Yuki Tsujikawa, Xiaoni Zhang, Masafumi Horio, Tetsuya Wada, Masashige Miyamoto, Toshihide Sumi, Fumio Komori, Takahiro Kondo, Iwao Matsuda
Summary: The growth of novel two-dimensional materials, especially boron-based, on Cu(110) substrate has shown great potential in exploring 1D anisotropic ordered phases and understanding their electronic properties. Through the deposition of boron atoms, a 3x1 ordered phase with anisotropic characteristics has been discovered, which exhibits similarity to carbon polymers like bumulene. This finding provides a new platform for investigating the properties of 1D boron materials and deepening our understanding of their potential applications.
Article
Nanoscience & Nanotechnology
Mina Maruyama, Nanami Ichinose, Yanlin Gao, Zheng Liu, Ryo Kitaura, Susumu Okada
Summary: Using the metal-organic chemical vapor deposition technique, a bilayer lateral heterostructure of MoS2 and WS2 was synthesized, showing complex type-II band edge alignments. The bilayer heterostructure exhibited gate-induced trans-dimensionality in carrier injection behavior, with carrier distributions varying from zero-to two-dimensional based on the applied gate voltage. This tunable carrier dimensionality has potential applications in various electronics fields.
ACS APPLIED NANO MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Masato Takei, Mihiro Takeuchi, Hiroshi Suga, Takatsugu Wakahara, Katsunori Wakabayashi, Susumu Okada, Kazuhito Tsukagoshi
Summary: Electromechanical switching was achieved in fullerene C-60 nanochains using a C-60 pyrrolidine tris-acid(CPTA) film in nanogap electrodes. A conductive C(60) chain formed spontaneously in the nanogap without electron beam irradiation. The switching operation from a high-resistance state to a low-resistance state was reproducible and could be executed at room temperature.
ACS APPLIED ELECTRONIC MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Hiroshi Ando, Masafumi Horio, Yoko Takeo, Masahito Niibe, Tetsuya Wada, Yasunobu Ando, Takahiro Kondo, Takashi Kimura, Iwao Matsuda
Summary: We developed a compact system for spectroscopic mapping of microstructures using a nano-focused beam at a synchrotron radiation soft X-ray beamline. The system consists of a Wolter mirror and a sample arranged with two mounting stages. It generates an 800-nm spot beam and maps the chemical distribution of non-uniform materials through near-edge X-ray fine structure spectroscopy. This system is suitable for experiments conducted with a nano-focused X-ray beam at synchrotron radiation beamlines or X-ray free-electron lasers. Additionally, this technical note provides guidelines for actual experiments.
E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY
(2023)
Article
Physics, Applied
Yanlin Gao, Susumu Okada
Summary: Using density functional theory and the effective screening medium method, we studied the energetics and electronic structure of bilayer Janus WSSe, focusing on their interlayer stacking arrangement. The energetics are sensitive to the interlayer stacking orientation and interface atomic arrangements, resulting from orbital hybridization between chalcogen atoms at the interfaces. The unique electronic structure of bilayer Janus WSSe is determined by the dipole moment arrangement of the constituent WSSe layers.
APPLIED PHYSICS EXPRESS
(2023)
Article
Chemistry, Physical
Shin-ichi Ito, Miwa Hikichi, Natsumi Noguchi, Mei Yuan, Zihao Kang, Kosei Fukuda, Masahiro Miyauchi, Iwao Matsuda, Takahiro Kondo
Summary: A method for achieving long-term stability of two-dimensional hydrogen boride (HB) sheets was developed by pre-treating the sheets and filtering the dried product. The treated sheets exhibited pure HB characteristics even after nine months of storage. This method is significant for preparing stable HB sheets without reactive species.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Tomonari Mizoguchi, Yanlin Gao, Mina Maruyama, Yasuhiro Hatsugai, Susumu Okada
Summary: We study characteristic electronic structures in an extended martini lattice model by investigating the minimal tight-binding model, and propose its materialization in pi-electron networks constructed by designated chemisorption on graphene and silicene. Remarkably, the unconventional gapless semiconductor with a flat band at the Fermi level can be realized by designated chemisorption or chemical substitution on graphene and silicene, and the electronic structure near the Fermi level is tunable by the choice of the atomic species of adsorbed atoms. Our results open the way to search exotic electronic structures and their functionalities induced by an extended martini lattice.
Article
Environmental Sciences
Ayumi Minoda, Shin-Ichi Miyashita, Takahiro Kondo, Toshihiko Ogura, Jing Sun, Yoshio Takahashi
Summary: Ion-exchange resins and activated carbons used in waste refinement in the electronics industry have low efficiency and high costs, while lyophilized cells of microalga Galdieria sulphuraria can recover palladium from diluted aqua regia more efficiently with higher recovery rates.
RESOURCES CONSERVATION & RECYCLING ADVANCES
(2023)
