Article
Physics, Multidisciplinary
F. Barantani, M. K. Tran, I. Madan, I. Kapon, N. Bachar, T. C. Asmara, E. Paris, Y. Tseng, W. Zhang, Y. Hu, E. Giannini, G. Gu, T. P. Devereaux, C. Berthod, F. Carbone, T. Schmitt, D. van der Marel
Summary: This study investigates the temperature dependence of the dd exciton spectrum in Bi2Sr2CaCu2O8-x crystals using resonant inelastic X-ray scattering. The study shows that there is a significant change in the dd exciton spectra when the material transitions from the normal state to the superconductor state.
Article
Multidisciplinary Sciences
Ta Tang, Brian Moritz, Cheng Peng, Zhi-Xun Shen, Thomas P. Devereaux
Summary: This study demonstrates that extended electron-phonon coupling is a significant factor in generating the attractive coupling observed in one-dimensional cuprate materials, and can reproduce the spectral features and doping dependence seen in experiments.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
X. Lou, T. L. Yu, Y. H. Song, C. H. P. Wen, W. Z. Wei, A. Leithe-Jasper, Z. F. Ding, L. Shu, S. Kirchner, H. C. Xu, R. Peng, D. L. Feng
Summary: CeOs4Sb12 (COS) and PrOs4Sb12 (POS) exhibit distinct properties of Kondo insulating and heavy fermion superconductivity, respectively, due to their different interactions between f electrons and conduction electrons. The study reveals the underlying microscopic differences, providing insight into the intriguing properties of these compounds.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Guochu Deng, Gang Zhao, Shuang Zhu, Zhenjie Feng, Wei Ren, Shixun Cao, Andrew Studer, Garry J. McIntyre
Summary: The spin dynamics of Mn4Nb2O9 were studied using inelastic neutron scattering, and a dynamic model was proposed to explain the observed spin-wave excitation spectrum. The study showed that the spin dynamics of this compound are dominated by antiferromagnetic interactions on the two MnO6 octahedron networks, and a spin gap and magnetic critical scattering were observed.
NEW JOURNAL OF PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Arun Parthasarathy, Egecan Cogulu, Andrew D. Kent, Shaloo Rakheja
Summary: This study discusses the precession and stability of the Neel order of antiferromagnets subjected to spin torque, focusing on the requirements for in-plane and normal components of spin polarization. The precessional motion is described as a damped-driven pendulum with hysteresis, showing critical values and frequency dependencies on the spin current.
Article
Multidisciplinary Sciences
Wei Wang, Jun Li, Zhixiu Liang, Lijun Wu, Pedro M. Lozano, Alexander C. Komarek, Xiaozhe Shen, Alex H. Reid, Xijie Wang, Qiang Li, Weiguo Yin, Kai Sun, Ian K. Robinson, Yimei Zhu, Mark P. M. Dean, Jing Tao
Summary: Understanding the driving mechanisms behind metal-insulator transitions (MITs) is crucial for controlling material properties. The nature of charge order and its role in the MIT of magnetite Fe3O4 have remained unclear. Recent research has found a nematic charge order in the high-temperature structure of Fe3O4, which competes with the lattice order and triggers the Verwey transition. This discovery uncovers an unconventional type of electronic nematicity and provides insights into the mechanism of transition in Fe3O4 via electron-phonon coupling.
Article
Materials Science, Multidisciplinary
Wenshan Hong, Honglin Zhou, Zezhong Li, Yang Li, Uwe Stuhr, Amit Pokhriyal, Haranath Ghosh, Zhen Tao, Xingye Lu, Jiangping Hu, Shiliang Li, Huiqian Luo
Summary: Based on inelastic neutron scattering measurements on a superconducting iron pnictide, a highly three-dimensional spin resonance mode with upward V-shape dispersion has been discovered, both in the ab plane and along the c axis. The c-axis dependence of both the resonance energy and its intensity in iron pnictides can be universally scaled with the distance between two adjacent Fe-As layers, suggesting the role of interlayer coupling in iron-based superconductivity. These results highlight the possibility of interlayer pairing driven by magnetic fluctuations under certain spin-orbit couplings.
Article
Physics, Multidisciplinary
Goetz Seibold, Riccardo Arpaia, Ying Ying Peng, Roberto Fumagalli, Lucio Braicovich, Carlo Di Castro, Marco Grilli, Giacomo Claudio Ghiringhelli, Sergio Caprara
Summary: A strange metallic state above the pseudogap temperature T-* in cuprates has puzzled scientists for a long time. Recent experiments have identified charge density fluctuations as a possible microscopic mechanism underlying this behavior, shedding light on the mysteries surrounding the strange metal phenomenology.
COMMUNICATIONS PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Wei-Jie Lin, W. LiMing, Tao Zhou
Summary: Recent experimental reports suggest that heavily overdoped monolayer graphene may exhibit superconductivity beyond the Van Hove regime. Theoretical studies have shown that a static spin-density-wave state could be favored in this doping region due to the nested Fermi surface at the Van Hove singularity point. Further research is needed to explore the possibility of spin excitations in the superconducting state.
Article
Physics, Multidisciplinary
Yang Chen, Weijin Chen, Xianghong Kong, Dong Wu, Jiaru Chu, Cheng-Wei Qiu
Summary: This study demonstrates strong coupling between quasibound states in the continuum of a high-Q metasurface, assisted with externally introduced enantiomers of weak chirality. A chirality-involved Hamiltonian is established to quantitatively describe the correlation between the coupling strength and the chirality of such systems, providing an insightful recipe for enhancing the coupling of resonant states further in the presence of quite weak chirality. The findings present a distinct strategy for manipulating optical coupling between resonances, revealing opportunities in chiral sensing, topological photonics, and quantum optics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Applied
Zhi-Xun Shen, Thomas Peter Devereaux
Summary: This article delves into the fundamental components of robust interactions within cuprates and discusses the influence of direct engagement with Prof. Muller on the authors' approach to the cuprate conundrum.
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
(2023)
Article
Materials Science, Multidisciplinary
H. C. Kao, Dingping Li, Baruch Rosenstein
Summary: This study shows that a one band Hubbard model with intermediate coupling can explain the two most important unusual properties of a normal state: linear resistivity strange metal and the pseudogap. By employing a relatively simple post-Gaussian approximation, both the spectroscopic and transport properties of the cuprates are considered at relevant temperatures. The research provides an alternative paradigm on the strength of the coupling required to describe the strange metal.
Article
Chemistry, Physical
Eleonora Vottero, Michele Carosso, Alberto Ricchebuono, Monica Jimenez-Ruiz, Riccardo Pellegrini, Celine Chizallet, Pascal Raybaud, Elena Groppo, Andrea Piovano
Summary: This study investigates the properties of a highly dispersed Pt/Al2O3 catalyst for industrial hydrogenation and dehydrogenation reactions using inelastic neutron scattering (INS) spectroscopy and DFT simulation. The results show that the INS spectra provide a unique fingerprint of the Pt/Al2O3 model morphology, size, H-coverage, and typology of Pt-H species.
Article
Nanoscience & Nanotechnology
Hiroya Kinoshita, Nobuaki Terakado, Yoshihiro Takahashi, Takamichi Miyazaki, Chitose Ishikawa, Koki Naruse, Takayuki Kawamata, Takumi Fujiwara
Summary: This study reports a method to fabricate nanosheets from La5Ca9Cu24O41 polycrystals and proposes an exfoliation model for nanosheet formation. This research is of great importance for the development of spin-ladder systems and strongly correlated cuprates.
NPJ 2D MATERIALS AND APPLICATIONS
(2022)
Article
Physics, Multidisciplinary
E. C. Marino
Summary: In this study, we investigate three fundamental issues in the physics of high-Tc cuprates from the perspective of a recently proposed comprehensive theory. These issues include the microscopic mechanism of the attractive interaction between holes, the relationship between the dispersion relation and the pseudogap order parameter, and the debate regarding the location of the quantum critical point. We obtained clearcut solutions for these three issues.
NEW JOURNAL OF PHYSICS
(2022)
Correction
Chemistry, Physical
Eva Y. Andrei, Allan H. MacDonald
Article
Physics, Multidisciplinary
Yafei Ren, Qiang Gao, A. H. MacDonald, Qian Niu
Summary: Graphene bilayers exhibit zero-energy flatbands at specific magic twist angles, satisfying a Dirac equation with a non-Abelian SU(2) gauge potential. A semiclassical WKB approximation scheme is developed to analyze these zero-energy solutions, finding values of a dimensionless Planck's constant that correspond closely to numerically determined twist angles.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Chao Lei, Bheema L. Chittari, Kentaro Nomura, Nepal Banerjee, Jeil Jung, Allan H. MacDonald
Summary: The study predicts that layer antiferromagnetic bilayers from van der Waals materials exhibit a strong magnetoelectric response, which can be controlled electrically for applications.
Article
Physics, Multidisciplinary
Wei Qin, Allan H. MacDonald
Summary: Recent research has shown that superconductivity in magic-angle twisted trilayer graphene can survive in in-plane magnetic fields well beyond the Pauli limit, unlike magic-angle twisted bilayer graphene. The difference is attributed to the symmetry and relative displacements present in trilayers, which are not under experimental control at present. An gate electric field can break the symmetry and limit the in-plane critical magnetic field.
PHYSICAL REVIEW LETTERS
(2021)
Article
Multidisciplinary Sciences
Xiaobo Lu, Biao Lian, Gaurav Chaudhary, Benjamin A. Piot, Giulio Romagnoli, Kenji Watanabe, Takashi Taniguchi, Martino Poggio, Allan H. MacDonald, B. Andrei Bernevig, Dmitri K. Efetov
Summary: The study observed multiple well-isolated flat moire bands in tBLG close to the second magic angle, which cannot be explained without considering electron-election interactions. High magnetic field magnetotransport measurements revealed an energetically unbound Hofstadter butterfly spectrum and the topologically nontrivial textures of the multiple moire bands.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Materials Science, Multidisciplinary
C. Lei, O. Heinonen, A. H. MacDonald, R. J. McQueeney
Summary: The study used classical Monte Carlo simulations and electronic structure models to calculate the ground state magnetic phase diagram, topological and optical properties of MBT films, finding that it is possible to prepare a variety of different magnetic stacking sequences, some of which have sufficient symmetry to disallow nonreciprocal optical response and Hall transport coefficients.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Chao Lei, A. H. MacDonald
Summary: The QAH effect in IMTIs thin films can be optimized and transitions between axion insulator/semimetal and Chern insulator/semimetal can be driven by electrical gate fields on a scale of around 10 meV/nm. This effect is described by combining a simplified coupled-Dirac-cone model of multilayer thin films with Schrodinger-Poisson self-consistent-field equations.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Multidisciplinary
Nicolas Morales-Duran, Nai Chao Hu, Pawel Potasz, Allan H. MacDonald
Summary: Moiré materials in two-dimensional semiconductor heterobilayers are quantum simulators that can simulate unconventional states of matter in Hubbard physics, such as spin liquids, insulating ferromagnets, and superconductors. The interaction between electrons or holes in Moiré materials is more relevant compared to atomic scale systems.
PHYSICAL REVIEW LETTERS
(2022)
Review
Nanoscience & Nanotechnology
Emma C. Regan, Danqing Wang, Eunice Y. Paik, Yongxin Zeng, Long Zhang, Jihang Zhu, Allan H. MacDonald, Hui Deng, Feng Wang
Summary: This Review discusses two approaches for realizing emergent excitonic physics in two-dimensional semiconductor heterostructures: the introduction of a moire superlattice and the formation of an optical cavity.
NATURE REVIEWS MATERIALS
(2022)
Review
Nanoscience & Nanotechnology
Libor Smejkal, Allan H. MacDonald, Jairo Sinova, Satoru Nakatsuji, Tomas Jungwirth
Summary: This review organizes the current understanding of anomalous antiferromagnetic materials that generate a Hall effect and discusses their applications in spintronics, topological condensed matter, and multipole magnetism.
NATURE REVIEWS MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yongxin Zeng, Allan H. MacDonald
Summary: This paper examines the influence of moiré patterns in semiconductor heterobilayers on exciton and trion states, comparing the differences to the case of excitons and trions in semiconductor quantum dots in the limit of strong moiré modulation potentials. The strategies for using optical properties as quantitative probes of moiré materials and the prospects of utilizing moiré materials to design unique light emitters are discussed.
Article
Materials Science, Multidisciplinary
B. Flebus, A. H. MacDonald
Summary: It has been found in recent experiments that phonons can be deflected by a magnetic field when flowing in response to a thermal gradient, leading to a thermal Hall effect. The ratio of phonon Hall conductivity ??H to the phonon longitudinal conductivity ??L in oxide dielectrics can exceed 10^-3 when phonon mean-free paths are longer than phonon wavelengths. Additionally, the ??H/??L ratio does not strongly depend on temperature. These observations suggest a mechanism related to phonon scattering from defects that break time-reversal symmetry, where Lorentz forces acting on charged defects result in significant skew-scattering amplitudes and related thermal Hall effects.
Article
Materials Science, Multidisciplinary
Yongxin Zeng, Fei Xue, Allan H. MacDonald
Summary: This study investigates the influence of an in-plane magnetic field and Coulomb interactions on the physics of quantum spin Hall insulators. By calculating phase diagrams and discussing possible experimental implications, the study demonstrates the system's instability against the formation of density-wave states when the band hybridization is weak and shows the appearance of distinct density-wave states as the strength of the in-plane magnetic field increases.
Article
Materials Science, Multidisciplinary
Dmitry K. Efimkin, Emma K. Laird, Jesper Levinsen, Meera M. Parish, Allan H. MacDonald
Summary: Recent studies have shown that the absorption properties of moderately doped two-dimensional semiconductors can be described in terms of exciton polarons, which exhibit classical charge-dipole behavior in the long-range limit and are only slightly modified for moderate doping. The dependence on doping can be well captured by a model with a phenomenological contact potential.
Article
Materials Science, Multidisciplinary
Jingtian Shi, Jihang Zhu, A. H. MacDonald
Summary: The quantum anomalous Hall (QAH) effect is sometimes observed in twisted bilayer graphene (tBG) when nearly aligned with an encapsulating hexagonal boron nitride (hBN) layer. The presence or absence of the QAH effect in individual devices is related to the commensurability between graphene/graphene and graphene/hBN moire patterns. The QAH effect is likely to occur when the moire patterns form a supermoire pattern near a commensurate point and have a percolating topologically nontrivial QAH phase.
