Article
Chemistry, Multidisciplinary
Jiashu Wang, William Powers, Zhan Zhang, Michael Smith, Bradlee J. McIntosh, Seul Ki Bac, Logan Riney, Maksym Zhukovskyi, Tatyana Orlova, Leonid P. Rokhinson, Yi-Ting Hsu, Xinyu Liu, Badih A. Assaf
Summary: This study investigates the behavior of candidate topological superconductor Sn1-xInxTe thin films in the presence of quantum confinement and lattice strain. The results reveal the coexistence of quantum interference effects and superconducting fluctuations above the critical temperature T-c. The analysis of normal state magnetoresistance indicates a transition from weak antilocalization to localization in the superconducting samples, suggesting that superconductivity primarily originates from charge carriers occupying trivial states. Additionally, a significant enhancement of conductivity is observed above T-c, indicating the presence of superconducting fluctuations.
Article
Chemistry, Multidisciplinary
Jiashu Wang, William Powers, Zhan Zhang, Michael Smith, Bradlee J. McIntosh, Seul Ki Bac, Logan Riney, Maksym Zhukovskyi, Tatyana Orlova, Leonid P. Rokhinson, Yi-Ting Hsu, Xinyu Liu, Badih A. Assaf
Summary: Research on strained Sn1-xInxTe thin films grown in the (111) plane reveals the potential hosting of Majorana zero modes and the existence of quantum interference effects and superconducting fluctuations in conductivity. The study also shows a crossover from weak antilocalization to localization in superconducting samples, indicating that superconductivity may mainly originate from charge carriers in strongly spin-orbit split trivial states. The observed significant increase in conductivity above T-c suggests the presence of superconducting fluctuations in the material.
Article
Nanoscience & Nanotechnology
Yangyang Fan, Xujing Li, Zhuo Yin, Aicong Geng, Mengqin Wang, Houbo Zhou, Zheng Wang, Xinchi Wang, Jing Wang, Fengxia Hu, Baohe Li, Jian-Tao Wang, Baogen Shen
Summary: The epitaxial strain has a significant influence on the magnetic states of LaCoO3 films. In this study, a robust long-range ferromagnetic ground state is observed in a tensile-strained LaCoO3 film on a SrTiO3 substrate, but the ferromagnetic state significantly attenuates when the film thickness is between 10 and 50 nm. The attenuation is speculated to be caused by the appearance of cross-hatched grain boundaries, which relax the tensile strain and result in local non-ferromagnetic phases. Magnetic force microscope observation confirms the correlation between non-ferromagnetic patterns and structural crosshatches, even at low temperatures and high magnetic fields, suggesting phase separation as the origin of magnetization attenuation.
Article
Physics, Multidisciplinary
Jin-Xin Hu, Cheng-Ping Zhang, Ying-Ming Xie, K. T. Law
Summary: The authors investigate the twisted bilayer WSe2 under strain and find that it exhibits a large nonlinear Hall effect that is highly sensitive to the topological properties of the material.
COMMUNICATIONS PHYSICS
(2022)
Article
Multidisciplinary Sciences
Meng Li, Geng Li, Lu Cao, Xingtai Zhou, Xiancheng Wang, Changqing Jin, Ching-Kai Chiu, Stephen J. Pennycook, Ziqiang Wang, Hong-Jun Gao
Summary: By using scanning tunneling microscopy/spectroscopy, an ordered and tunable Majorana zero mode (MZM) lattice has been discovered in naturally strained LiFeAs superconductor. This finding provides a new pathway for future topological quantum computation.
Article
Physics, Multidisciplinary
Qiang Gao, Junkai Dong, Patrick Ledwith, Daniel Parker, Eslam Khalaf
Summary: This article proposes a setup based on periodically strained graphene that reproduces key aspects of twisted moire heterostructures. The system has almost ideal flat bands with valley-resolved Chern number +/- 1, exhibiting larger interaction-induced gaps and smaller quasiparticle dispersion compared to twisted graphene systems.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Sara Conti, Samira Saberi-Pouya, Andrea Perali, Michele Virgilio, Francois M. Peeters, Alexander R. Hamilton, Giordano Scappucci, David Neilson
Summary: By confining holes in a compressively strained Germanium quantum well and electrons in a lattice-matched tensile strained Silicon quantum well in a lattice-matched strained Si/Ge bilayer embedded into a Germanium-rich SiGe crystal, observable mass-imbalanced electron-hole superfluidity and BEC can be achieved, potentially leading to superfluidity at experimentally accessible temperatures.
NPJ QUANTUM MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Swagata Acharya, Dimitar Pashov, Elena Chachkarova, Mark van Schilfgaarde, Cedric Weber
Summary: Sr2RuO4 transitions from a normal Fermi liquid to a superconducting phase at around 1 K, but the superconducting state remains poorly understood. Critical temperatures can be enhanced by applying uniaxial strain, but decrease after reaching a critical strain. An instability approach reveals tendencies to competing ground states under different strains, showing changes in singlet and triplet instabilities in the normal Fermi liquid phase under strain conditions.
APPLIED SCIENCES-BASEL
(2021)
Article
Materials Science, Multidisciplinary
Ohad Antebi, Ady Stern, Erez Berg
Summary: Three symmetries prevent a twisted bilayer of graphene from developing an in-plane spontaneous magnetization in the absence of a magnetic field. Experimental and theoretical indications suggest that these symmetries may be broken spontaneously under certain conditions. In such cases, the in-plane orbital magnetization serves as a sensitive probe for detecting the simultaneous breaking of these three symmetries.
Article
Nanoscience & Nanotechnology
K. S. Takahashi, Y. Tokura, M. Kawasaki
Summary: Carrier doping in two-dimensional Mott insulators is a strategy for exploring quantum phenomena. This study demonstrates the collapse of the Mott insulator state in a two-dimensional system by fabricating well-defined SrVO3 films and doping LaxSr1-xVO3.
Article
Chemistry, Multidisciplinary
Eti Barazani, Dip Das, Chubin Huang, Abhishek Rakshit, Cecile Saguy, Pavel Salev, Javier del Valle, Maytal Caspary Toroker, Ivan K. K. Schuller, Yoav Kalcheim
Summary: The effects of strain on the metal-insulator phase transitions in V2O3 are explored. It is found that the expansion of the ab-plane is crucial for inducing negative pressure effects in the films. The findings provide insights into manipulating a Mott transition in V2O3 and expanding its potential applications in electronics.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Bing Huang, Hengyue Xu, Nannan Jiang, Minghao Wang, Jianren Huang, Lunhui Guan
Summary: In this study, a Co-HMT metal-organic framework was used as the precursor, and a fast-quenching method was employed to synthesize a catalyst with RuO2 nanorods loaded on ATO. The optimized catalyst exhibited a small overpotential and stable performance, enabling it to reach a certain current density at a low voltage in practical applications.
Article
Chemistry, Physical
Bouchra Asbani, Kevin Robert, Pascal Roussel, Thierry Brousse, Christophe Lethien
Summary: The research presents an asymmetric micro-supercapacitor design using VN and hRuO(2) films to achieve high cell voltage and specific capacitance values in 1 M KOH electrolyte. The energy density of the asymmetric VN/hRuO(2) micro-supercapacitor is significantly higher compared to symmetric microdevices, demonstrating a 5-fold enhancement factor.
ENERGY STORAGE MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Jeongkeun Song, Eun Kyo Ko, Sangmin Lee, Junsik Mun, Ji Hwan Jeong, Jong Hwa Lee, Woo Jin Kim, Miyoung Kim, Yangyang Li, Ji Hye Lee, Tae Won Noh
Summary: We demonstrate a method to control impurities and defects in strained Nd2Ir2O7 (NIO-227) films by compensating for iridium loss during growth. Increasing the amount of IrO2 ablated enhances the quality and electrical transport properties of the fabricated films. The anomalous Hall effects of the films have a strong dependency on the amount of IrO2 ablated, attributed to the structural inhomogeneity in the NIO-227 films.
Article
Materials Science, Multidisciplinary
Nicholas G. Combs, Hanbyeol Jeong, Ryan Russell, Linus Kautzsch, Tyler N. Pardue, Thomas E. Mates, Stephen D. Wilson, John W. Harter, Susanne Stemmer
Summary: We investigated the effect of alloying with Eu on the superconductivity and ferroelectricity of compressively strained Sm-doped films of EuxSr1-xTiO3. We found that superconductivity can still survive when the alloying concentration of Eu is x=0.14. However, at x=0.09, there is no suppression of the superconducting transition temperature but a significant reduction in the upper critical field (Hc2). In addition, these films lack the sharp ferroelectric transition observed in films without Eu. We propose that Eu alloying leads to a crossover from a globally ordered ferroelectric state to one with only short-range polar order.
Article
Chemistry, Multidisciplinary
Ziqian Wang, Meng Gao, Tonghua Yu, Siyuan Zhou, Mingquan Xu, Motoaki Hirayama, Ryotaro Arita, Yuki Shiomi, Wu Zhou, Naoki Ogawa
Summary: Stacking order plays a significant role in the properties of van der Waals layered magnets, and recent studies suggest possible different stackings in few-layer crystals. This study combines atomic-scale electron microscopy and theoretical calculations to show that while the bulk stacking persists in bilayers of MnPS3, the local rippling effect lifts the monoclinic symmetry of the few layers. This finding reveals the impact of rippling on the microscopic symmetry of two-dimensional materials and suggests the possibility of approaching the two-dimensional Neel antiferromagnetic honeycomb lattice in MnPS3 without reaching monolayer thickness.
Article
Chemistry, Multidisciplinary
Tomohiro Hori, Naoya Kanazawa, Motoaki Hirayama, Kohei Fujiwara, Atsushi Tsukazaki, Masakazu Ichikawa, Masashi Kawasaki, Yoshinori Tokura
Summary: Strongly spin-orbit coupled states in metal interfaces, topological insulators, and 2D materials have great potential for spintronics. However, there are still challenges in integrating them into silicon electronics and dealing with the scarcity of constituent heavy elements. This study demonstrates robust spin-orbit coupling properties of a ferromagnetic topological surface state in FeSi and their controllability through hybridization with adjacent materials. The enhanced magnetic properties enable room-temperature magnetization switching, making it applicable for spin-orbit torque-based spintronic devices.
ADVANCED MATERIALS
(2023)
Article
Multidisciplinary Sciences
Xianzhe Chen, Tomoya Higo, Katsuhiro Tanaka, Takuya Nomoto, Hanshen Tsai, Hiroshi Idzuchi, Masanobu Shiga, Shoya Sakamoto, Ryoya Ando, Hidetoshi Kosaki, Takumi Matsuo, Daisuke Nishio-Hamane, Ryotaro Arita, Shinji Miwa, Satoru Nakatsuji
Summary: The tunnelling magnetoresistance (TMR) in magnetic tunnel junctions (MTJs) is usually studied in ferromagnetic materials, but this study reports the observation of TMR in an all-antiferromagnetic tunnel junction. A TMR ratio of about 2% was measured at room temperature, which is attributed to the configuration of cluster magnetic octupoles in the chiral antiferromagnetic state. Sign and direction of anisotropic longitudinal spin-polarized current in the antiferromagnet can be controlled by octupole direction. Theoretical analysis suggests that the chiral antiferromagnetic MTJ can produce a substantially large TMR ratio due to the time-reversal, symmetry-breaking polarization characteristic of cluster magnetic octupoles.
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
Physics, Applied
M. Ohno, T. C. Fujita, M. Kawasaki
Summary: The research team successfully achieved the epitaxial stabilization of pyrochlore Bi2Rh2O7 on Y-stabilized ZrO2 (YSZ) (111) substrate by inserting a pyrochlore Eu2Ti2O7 template layer, instead of forming Bi-based layered structures directly on the YSZ (111) substrate. This study demonstrates the importance of iso-structural crystal phase in interfacial phase control. The Bi2Rh2O7 film exhibits p-type electrical conduction with the lowest longitudinal resistivity (?(xx)) among reported Rh pyrochlore oxides, and shows almost no temperature dependence in the measured range of 2-300 K for parameters such as ?(xx), carrier density, and mobility.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Masao Nakamura, Ryuichi Namba, Takahiro Yasunami, Naoki Ogawa, Yoshinori Tokura, Masashi Kawasaki
Summary: This study identifies the two distinct quantization effects of spatially confined excitons in a 2D semiconductor PbI2, the enhanced binding energy under strong confinement and the center-of-mass quantization under weak confinement. The transition between these effects is revealed in high-quality epitaxial thin films, providing important insights for the development of optoelectronic functionalities of 2D materials.
APPLIED PHYSICS LETTERS
(2023)
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
Nanoscience & Nanotechnology
N. Takahara, K. S. Takahashi, K. Maruhashi, Y. Tokura, M. Kawasaki
Summary: EuTiO3 (ETO) is a unique magnetic semiconductor with a large localized magnetic moment of Eu2+. By doping high-mobility electrons in the conduction band, peculiar magnetotransport properties have been observed. In this study, the physical properties of high quality ETO films with La3+ or Gd3+ donors grown on nearly lattice matched substrates are examined. These transport properties provide a deeper understanding of the band structure topology in high-mobility, magnetic oxide semiconductors.
Article
Nanoscience & Nanotechnology
Motoharu Kitatani, Yusuke Nomura, Motoaki Hirayama, Ryotaro Arita
Summary: Motivated by recent theoretical materials design, we calculate the phase diagram of RbCa2NiO3 and A(2)NiO(2)Br(2) using the dynamical vertex approximation. We find that these nickelates exhibit similar phase features as cuprates, where superconductivity emerges from hole-doped antiferromagnetic Mott insulators with a dome-like superconducting transition temperature. This highlights the crucial role of electron correlations in nickelate superconductors, which can be controlled by modifying the block layers.
Article
Chemistry, Multidisciplinary
Tianchun Wang, Takuya Nomoto, Takashi Koretsune, Ryotaro Arita
Summary: We performed first-principles Eliashberg calculations for several conventional superconductors, investigating the importance of self-consistency in the calculation. By comparing the self-consistent results with the one-shot calculation results for the self-energy of electrons, we found that the difference between them becomes larger for systems with rapidly changing density of states around the Fermi level, such as those with van Hove singularities in pressurized hydrides.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(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
F. Schilberth, M. -C. Jiang, S. Minami, M. A. Kassem, F. Mayr, T. Koretsune, Y. Tabata, T. Waki, H. Nakamura, G. -Y. Guo, R. Arita, I. Kezsmarki, S. Bordacs
Summary: Through experimental and theoretical studies using broadband polarized reflectivity and magneto-optical Kerr effect spectroscopy, we have discovered giant anomalous Hall effect and magneto-optical activity in the magnet Co3Sn2S2 with topological nontrivial degeneracies, primarily generated by strongly tilted nodal-line segments around the Fermi energy. This finding is of significant importance for understanding the physical properties of magnetic topological materials.
Article
Materials Science, Multidisciplinary
Katsuhiro Tanaka, Takuya Nomoto, Ryotaro Arita
Summary: We investigate the tunneling magnetoresistance (TMR) effect using lattice models for magnetic tunnel junctions (MTJs). By analyzing the local density of states (LDOS) at the center of the barrier, we find that it qualitatively traces the TMR effect. The LDOS contains information on the electrodes and electron tunneling, allowing for a more precise evaluation of tunneling conductance. Furthermore, our findings show that the TMR effect in ferrimagnetic MTJs can be influenced by interfacial magnetic structures, which can also be captured by the LDOS.
Article
Materials Science, Multidisciplinary
Tatsuto Hatanaka, Takuya Nomoto, Ryotaro Arita
Summary: Transition metal dichalcogenides (TMDs) exhibit various magnetic structures through intercalation of other transition metal atoms. To understand the chemical trend of the magnetic properties, we conducted a first-principles study on 48 compounds with different hosts, guests, and composition ratios. By applying spin density functional theory and the local force method, we derived classical spin models that are consistent with experimental results and explained the chemical trend in terms of 3d orbital occupancy. These findings can guide the prediction of magnetic structures in yet-to-be-synthesized compounds.
Article
Materials Science, Multidisciplinary
Steffen Backes, Yuta Murakami, Shiro Sakai, Ryotaro Arita
Summary: Recent developments in quantum hardware and algorithms have enabled us to address problems in quantum chemistry and condensed-matter physics using current noisy intermediate-scale quantum devices. In this study, we demonstrate the solution of the dynamical mean-field theory (DMFT) impurity problem for the Hubbard-Holstein model on the IBM Quantum Processor Kawasaki. We encode both fermionic and bosonic degrees of freedom on the quantum device and use a Krylov variational quantum algorithm to obtain the impurity Green's function, achieving high accuracy.
