Article
Optics
D. D. Su, C. K. Li, Q. Su, R. Grobe
Summary: Examined the laser-assisted electron-positron pair-creation process and found that the phase properties of the core electron can be transferred to the positron during the creation process. The creation probability of the positron is different for different phases, suggesting that the vacuum decay process can sense phase.
Article
Chemistry, Physical
Gian Marco Pierantozzi, Giovanni Vinai, Aleksandr Yu Petrov, Alessandro De Vita, Federico Motti, Vincent Polewczyk, Debashis Mondal, Tommaso Pincelli, Riccardo Cucini, Chiara Bigi, Ivana Vobornik, Jun Fujii, Piero Torelli, Francesco Offi, Giorgio Rossi, Giancarlo Panaccione, Francesco Borgatti
Summary: In this study, the relationship between ferromagnetism and metallicity in strained La0.67Ca0.33MnO3 films was investigated. It was found that the half-metallicity of the ferromagnetic metallic (FMM) phase is correlated with spin polarization and occupancy at the Fermi level. These results suggest that the half-metallic behavior predicted by a double-exchange model persists even in phase-separated manganites.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Multidisciplinary Sciences
Stephan G. J. Philips, Sergey Amitonov, Sander L. de Snoo, Maximilian Russ, Nima Kalhor, Christian Volk, William I. L. Lawrie, Delphine Brousse, Larysa Tryputen, Brian Paquelet Wuetz, Amir Sammak, Menno Veldhorst, Giordano Scappucci, Lieven M. K. Vandersypen
Summary: Future quantum computers require a large number of reliable qubits, but this is typically conflicting with high fidelity operations. In this study, a six-qubit processor was designed and operated with high fidelities for universal operation, state preparation, and measurement, using careful Hamiltonian engineering and efficient calibration. These advances are a major stepping stone towards large-scale quantum computers.
Article
Chemistry, Physical
Evgenii Sterkhov, Nikolay M. Chtchelkatchev, Elena Mostovshchikova, Roman E. Ryltsev, Sergey A. Uporov, Gheorghe L. Pascut, Andrey Fetisov, Svetlana G. Titova
Summary: PrBaMn2O6 with ordered alternate stacking of PrMnO3/BaMnO3 layers exhibits two magnetic phase transitions close to room temperature, making it a promising magnetocaloric and magnetoresistive material. The experimentally detected structural transition is attributed to the splitting of eg-doublet states due to the tendency towards orbital ordering at the metal-insulator phase transition.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Alexander B. Shick, Shin-ichi Fujimori, Warren E. Pickett
Summary: Correlated band theory based on density functional theory with exact diagonalization was applied to UTe2, revealing its physical properties at different U values, including a transition to a semimetallic state at U = 3 eV. Predictions were made for the Kondo temperature of UTe2 and the electric field gradient difference between uranium and tellurium sites, consistent with experimental observations.
Article
Chemistry, Multidisciplinary
Xiangyan Han, Qianling Liu, Yijie Wang, Ruirui Niu, Zhuangzhuang Qu, Zhiyu Wang, Zhuoxian Li, Chunrui Han, Kenji Watanabe, Takashi Taniguchi, Zhida Song, Jinhai Mao, Zheng Vitto Han, Zizhao Gan, Jianming Lu
Summary: Rhombohedral trilayer graphene is a natural flat-band platform for studying interaction-driven symmetry-breaking phases. The displacement field can further flatten the band and enhance the density of states, controlling the energy balance between spin and valley degrees of freedom. In this work, the authors characterized the isospin flavor polarization and developed a method to measure the chemical potential at a fixed displacement field, allowing for the extraction of energy variation during phase transitions. This work opens opportunities for the thermodynamic characterization of displacement-field tuned van der Waals heterostructures.
Article
Engineering, Mechanical
Shaghayegh Sadat Babaei, Jahanshir Mohammadzadeh-Habili, Sayed Mohammadali Zomorodian
Summary: The study introduces and investigates the quarter-circular gate, deriving equations for discharge coefficient and velocity distribution at the gate opening section. Experimental data validates the high precision of the proposed theory, showing that the downstream flow depth of the quarter-circular gate is uniform and its discharge coefficient is significantly larger than traditional gates. The elimination of the contraction section at the downstream of gate opening contributes to the larger discharge coefficient of the quarter-circular gate.
FLOW MEASUREMENT AND INSTRUMENTATION
(2021)
Article
Materials Science, Multidisciplinary
J. Willwater, N. Steinki, D. Menzel, R. Reuter, H. Amitsuka, V Sechovsky, M. Valiska, M. Jaime, F. Weickert, S. Suellow
Summary: A detailed study of the magnetic and electronic properties of U2Rh3Si5, including the establishment of magnetic phase diagrams for all crystallographic directions, has been conducted. The possibility of an electronic phase above the Neel temperature as a precursor of a magnetic phase has also been discussed.
Article
Chemistry, Inorganic & Nuclear
Frank Stegemann, Arthur Mar
Summary: LaHf2Ni5-xAs4 is a new quaternary arsenide with monoclinic crystal structure, where As-centered trigonal prisms are arranged in propeller-shaped units linked together by single trigonal prisms. The compound displays metallic conductivity, mainly attributed to interactions between Hf-Hf and Hf-Ni.
JOURNAL OF SOLID STATE CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Hang Li, Yulin Gan, Marius-Adrian Husanu, Rasmus Tindal Dahm, Dennis Valbjorn Christensen, Milan Radovic, Jirong Sun, Ming Shi, Baogen Shen, Nini Pryds, Yunzhong Chen
Summary: This study investigates the metallic band dispersion at the LaAlO3/SrTiO3 heterointerface using soft X-ray angle-resolved photoemission spectroscopy. The results show that the insertion of a LaMnO3 buffer layer not only enhances the electron mobility, but also makes the electronic structure robust against X-ray radiation. Moreover, the buffer layer strongly suppresses the formation of oxygen vacancies and the electron-phonon interaction on the SrTiO3 side.
Article
Multidisciplinary Sciences
Andrew Hardy, Arijit Haldar, Arun Paramekanti
Summary: We propose and study a two-orbital lattice extension of the Sachdev-Ye-Kitaev model in the large-N limit. The phase diagram of this model features a high-temperature isotropic non-Fermi liquid which undergoes first-order thermal transition into a nematic insulator or continuous thermal transition into a nematic metal phase, separated by a tunable tricritical point. These phases arise from spontaneous partial orbital polarization of the multiorbital non-Fermi liquid. We explore the spectral and transport properties of this model, including d.c. elastoresistivity, which exhibits a peak near nematic transition, as well as nonzero frequency elastoconductivity. Our work offers a useful perspective on nematic phases and transport in correlated multiorbital systems.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Materials Science, Multidisciplinary
Katsunori Kubo
Summary: The investigation of the two-orbital Hubbard model on a square lattice reveals that introducing next-nearest-neighbor hopping can change the magnetic properties of the system, leading to a transition to a ferromagnetic state under certain conditions.
Article
Automation & Control Systems
Jing Na, Yingbo Huang, Xing Wu, Yan-Jun Liu, Yunpeng Li, Guang Li
Summary: A reliable, efficient, and simple control method for a quarter-car active suspension system is proposed, which does not use function approximation and effectively accommodates unmolded dynamics. The control ensures both transient and steady-state suspension performance, improving computational efficiency and simplifying parameter tuning. Experimental results demonstrate superior performance and computational efficiency compared to other control methods.
IEEE TRANSACTIONS ON SYSTEMS MAN CYBERNETICS-SYSTEMS
(2022)
Article
Materials Science, Multidisciplinary
Da Lan, Pingfan Chen, Chao Liu, Xiaohan Wu, Ping Yang, Xiaojiang Yu, Jun Ding, Jingsheng Chen, Gan Moog Chow
Summary: The study investigates tunable domain structures in ferroelastic La0.67Sr0.33MnO3 (LSMO) films through interfacial engineering, demonstrating a significant influence of crystal orientation on domain structures. The structural domains in LSMO films are controlled by anisotropic strain and interfacial oxygen octahedral coupling at the heterointerface between LSMO and NdGaO3 (NGO).
Article
Chemistry, Physical
Roland Bliem, Dongha Kim, Jiayue Wang, Ethan J. Crumlin, Bilge Yildiz
Summary: The study demonstrates that the surface segregation of Sr in La0.8Sr0.2MnO3 (LSM) can be stabilized at high temperatures by using Hf as a submonolayer coverage. Hf-modified regions on the LSM surface exhibit significantly less Sr surface segregation, attributed to Hf reducing the surface oxygen vacancy concentration and thus diminishing the electrostatic attraction between Sr2+ cations and surface oxygen vacancies. The direct role of metal species in the stabilization process is highlighted through physical vapor deposition, broadening the relevance of metal doping on the surfaces of perovskite oxides.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Multidisciplinary
Aki Kitaori, Naoya Kanazawa, Takanori Kida, Yasuo Narumi, Masayuki Hagiwara, Koichi Kindo, Tetsuya Takeuchi, Ai Nakamura, Dai Aoki, Yoshinori Haga, Yoshio Kaneko, Yoshinori Tokura, Yoshichika O. Nuki
Summary: We have successfully grown single crystalline Tb5Sb3 with a hexagonal structure, which exhibits complex spiral magnetic structures with changing temperature. Specific heat and magnetization measurements revealed one clear magnetic transition at 133 K. The magnetic structure is oriented in the hexagonal basal plane with a hard axis corresponding to the [0001] direction. Below 50 K, the magnetic structure undergoes a transformation, leading to a rapid decrease in magnetic susceptibility for H II [1010] and a kink behavior in low-field magnetization, while showing hysteresis in the magnetization curve.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Letter
Physics, Multidisciplinary
Minoru Kawamura, Masataka Mogi, Ryutaro Yoshimi, Takahiro Morimoto, Kei S. Takahashi, Atsushi Tsukazaki, Naoto Nagaosa, Masashi Kawasaki, Yoshinori Tokura
Summary: Adiabatic charge pumping is observed in a thin-film magnetic heterostructure of topological insulators, confirming the theoretical prediction of topological magnetoelectric effect. The pumped charge is proportional to the surface Hall conductivity, providing clues for its direct observation.
Article
Chemistry, Multidisciplinary
Shimpei Ono
Summary: Recently, electronic devices that utilize the electric double layers of ions have provided research opportunities in various fields and are considered to be the future of iontronics devices. These devices act as nanogap capacitors, enabling low-power operation and new functional devices. By controlling the motion of ions, ions can be used as semi-permanent charge to form electrets, leading to advanced applications and energy harvesters in iontronics devices.
Article
Physics, Multidisciplinary
H. Takagi, R. Takagi, S. Minami, T. Nomoto, K. Ohishi, M. -t. Suzuki, Y. Yanagi, M. Hirayama, N. D. Khanh, K. Karube, H. Saito, D. Hashizume, R. Kiyanagi, Y. Tokura, R. Arita, T. Nakajima, S. Seki
Summary: The spontaneous topological Hall effect in triangular lattice compounds CoTa3S6 and CoNb3S6 is experimentally demonstrated, combining non-coplanar antiferromagnetic order with finite scalar spin chirality in the absence of a magnetic field. These compounds exhibit unconventionally large spontaneous Hall effects despite their small net magnetization, and the mechanism behind this phenomena is explained by the topological Hall effect associated with scalar spin chirality. The results suggest that the scalar spin chirality mechanism offers a promising route for the realization of a giant spontaneous Hall response in compensated antiferromagnets.
Article
Physics, Multidisciplinary
T. Nomura, X. -X. Zhang, R. Takagi, K. Karube, A. Kikkawa, Y. Taguchi, Y. Tokura, S. Zherlitsyn, Y. Kohama, S. Seki
Summary: The nonreciprocal acoustic properties of a room-temperature ferromagnet Co9Zn9Mn2 unveil the phonon magnetochiral effect close to room temperature. In contrast to the insulating Cu2OSeO3, the nonreciprocity in this metallic compound is enhanced at higher temperatures and observed up to 250 K. Ultrasound and microwave-spectroscopy experiments suggest that the magnitude of the phonon magnetochiral effect mostly depends on the Gilbert damping of Co9Zn9Mn2, which increases at low temperatures and hinders the magnon-phonon hybridization. It is also proposed that the phonon nonreciprocity can be further enhanced by engineering the magnon band of materials.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Kamil K. Kolincio, Max Hirschberger, Jan Masell, Taka-hisa Arima, Naoto Nagaosa, Yoshinori Tokura
Summary: Dynamical spin fluctuations in magnets can be influenced by lattice geometry, leading to chiral spin fluctuations and fluctuation-related transport anomalies. This study focuses on the crucial role of lattice geometry on chiral spin fluctuations and the quantum-mechanical phase of conduction electrons. Experimental results and Monte Carlo calculations suggest that lattices with dissimilar plaquettes exhibit the most promising Berry phase phenomena in paramagnets.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Keisuke Matsuura, Yo Nishizawa, Markus Kriener, Takashi Kurumaji, Hiroshi Oike, Yoshinori Tokura, Fumitaka Kagawa
Summary: In some materials, the equilibrium phase-transition line is concealed by the hysteresis region associated with field-induced first-order transitions (FOTs). Phase diagrams are essential in material science, as they provide comprehensive information about thermodynamic quantities. However, determining the equilibrium phase-transition line in a field-induced FOT is challenging, especially in the presence of large hysteresis.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Multidisciplinary
Shingo Toyoda, Jiou-Cing Liao, Guang-Yu Guo, Yusuke Tokunaga, Taka-hisa Arima, Yoshinori Tokura, Naoki Ogawa
Summary: We report a giant magnetic-field effect on optical second-harmonic generation (SHG) in a noncentrosymmetric ferrimagnet Eu2MnSi2O7. The SHG intensity changes at visible photon energy of 2.8 eV by more than 7000% upon the reversal of magnetic-field direction. Such pronounced modulation of the nonlinear optical activity results from an interference between crystallographic and magnetically induced nonlinear polarization. The amplitude of these nonlinear optical susceptibilities is controlled by the spin alignment and the light incident angle, enabling to optimize the magnetic switching of SHG in detail.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Junya Katsumata, Fumiya Osawa, Go Sato, Atsushi Sato, Kazumoto Miwa, Shimpei Ono, Kazuhiro Marumoto
Summary: The operation mechanism of light-emitting electrochemical cells (LECs) is investigated through operando observation of spin states. It is found that both electron spin resonance and light emission increase as the voltage applied to LECs increases, indicating a correlation between the distribution of electrochemically doped charges and the luminance increase. Furthermore, the molecular orientation of electrochemically charge-doped Super Yellow is deduced.
COMMUNICATIONS MATERIALS
(2023)
Article
Multidisciplinary Sciences
Yoshihiro D. Kato, Yoshihiro Okamura, Max Hirschberger, Yoshinori Tokura, Youtarou Takahashi
Summary: The study reveals the magneto-optical Kerr effect (MOKE) induced by the formation of magnetic skyrmions in Gd2PdSi3, referred to as topological MOKE. The presence of skyrmions leads to a significant enhancement of the optical rotation, exemplifying the light-skyrmion interaction arising from the emergent gauge field. The findings pave the way for photonic technology based on skyrmionics.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Shunsuke Kitou, Yoshio Kaneko, Yuiga Nakamura, Kunihisa Sugimoto, Yusuke Nomura, Ryotaro Arita, Yoshinori Tokura, Hiroshi Sawa, Taka-hisa Arima
Summary: By performing core differential Fourier synthesis (CDFS) analysis of high-energy X-ray diffraction data, we directly observe the distribution state of Mo 4d orbital electrons in a pyrochlore-type oxide Nd2Mo2O7 at subangstrom resolution. The obtained valence electron density (VED) distribution confirms the Mo4+ 4d2 orbital state, and a dip in the radial profile indicates a node of the 4d wave function. The VED distribution around the Nd site is attributed to the hybridization of neighboring O 2p with Nd 6s/6p/5d orbitals and the anisotropic Nd3+ 4f3 electrons, which cannot be explained by simple j-j or LS coupling models. This study demonstrates the usefulness of CDFS analysis in investigating orbital states in crystalline materials.
Article
Materials Science, Multidisciplinary
Y. H. Zhuang, H. W. Liu, Y. H. Li, Y. M. Chang, T. Kurumaji, Y. Tokura, Y. M. Sheu
Summary: This study reveals the crucial role of crystal-field excitations involving spin-flip transitions in controlling switchable optomagnet effects in antiferromagnetic (Fe0.875Zn0.125)2Mo3O8. The photoinduced magnetization does not occur until the flipped spins are in excited states that frustrate the balanced spin moments, and it only starts to grow from a zero moment after the ultrashort pulses disappear. Through Kerr-effect microscopy and application of magnetic fields, the study distinguishes between photoinduced switchable magnetization and nonswitchable demagnetization. The experimental designs uncover essential factors for the development of antiferromagnetic memory devices using insulating oxides.
Article
Materials Science, Multidisciplinary
M. Ogino, Y. Kaneko, Y. Tokura, Y. Takahashi
Summary: We investigate the nonreciprocity of photons caused by enhanced dynamical magnetoelectric (ME) coupling in multiferroic perovskite manganites. The correlation between the optical ME effects and the order parameters is examined by changing the composition of the manganites. Nonreciprocal directional dichroism and gyrotropic birefringence are demonstrated in different spin-cycloidal phases, and their magnitudes show deviations from the relevant coupled order parameters.
Article
Materials Science, Multidisciplinary
Jiwon Ju, Hiraku Saito, Takashi Kurumaji, Max Hirschberger, Akiko Kikkawa, Yasujiro Taguchi, Taka-hisa Arima, Yoshinori Tokura, Taro Nakajima
Summary: We investigated the magnetic structures of Gd2PdSi3, a centrosymmetric skyrmion material, using polarized neutron scattering. Our results confirmed the elliptic screw-type magnetic modulation in zero field with a propagation vector of (q, 0, 0). As the temperature increases, the system undergoes a magnetic phase transition while maintaining the incommensurate q-vector of (q, 0, 0). In the ground state, the system contains equal fractions of left-handed and right-handed screw-type orders, as expected from the centrosymmetric crystal structure.
Article
Materials Science, Multidisciplinary
Aki Kitaori, Jonathan S. White, Naoya Kanazawa, Victor Ukleev, Deepak Singh, Yuki Furukawa, Taka-hisa Arima, Naoto Nagaosa, Yoshinori Tokura
Summary: AC current-driven motions of spiral spin textures can create new electric fields and induce emergent electromagnetic induction effect, potentially realizing quantum inductor elements of micrometer size. Research on YMn6Sn6 helimagnet reveals the optimized conditions for emergent inductors beyond room temperature, achieved by modifying the magnetism through partial substitution of Y by Tb. The study demonstrates the control of both magnitude and sign of emergent electromagnetic inductance, and expands the range of potential candidate materials for emergent inductors.