Article
Materials Science, Multidisciplinary
Luc Testa, Vinko Surija, Krunoslav Prsa, Paul Steffens, Martin Boehm, Philippe Bourges, Helmuth Berger, Bruce Normand, Henrik M. Ronnow, Ivica Zivkovic
Summary: This study using inelastic neutron scattering measurements on the spin-1/2 antiferromagnet SeCuO3 shows that the compound exhibits all three primary types of spin excitation: spin waves, triplons, and spinons. The Cu-2 sites in the compound form strongly bound dimers, while the Cu-2 sites form a network of spin chains.
Article
Materials Science, Multidisciplinary
Alexander Mook, Rhea Hoyer, Jelena Klinovaja, Daniel Loss
Summary: We study quantum condensed matter systems where particle number is not conserved, leading to topological anticrossings in the spectrum due to hybridization of states from different particle-number sectors. This phenomenon is observed in fully saturated spin-anisotropic quantum magnets, where single magnons hybridize with magnon bound pairs. The resulting chiral edge excitations are composite particles with mixed spin-multipolar character, showing genuine quantum mechanical effects that vanish in the classical limit. These findings have implications for intrinsic anomalous Hall-type transport, suggesting that fully polarized quantum magnets can serve as a promising platform for studying topological effects caused by hybridizations between particle-number sectors.
Article
Chemistry, Multidisciplinary
Kirill O. Nikolaev, Stephanie R. Lake, Georg Schmidt, Sergej O. Demokritov, Vladislav E. Demidov
Summary: This study successfully demonstrates spin-wave devices that can operate without an external magnetic field using submicrometer wide waveguides. The experimental results show that these waveguides have a highly stable magnetic configuration at zero field and support long-range propagation of spin waves. These findings provide the basis for the development of energy-efficient zero-field spin-wave devices and circuits.
Article
Materials Science, Multidisciplinary
L. Stoppel, S. Hayashida, Z. Yan, A. Podlesnyak, A. Zheludev
Summary: In the S = 1 easy-plane-type triangular antiferromagnets CsFeCl3 and RbFeCl3, magnetic excitations were investigated using a combination of inelastic neutron scattering measurements and spin-wave theory calculations. An established exchange-coupling Hamiltonian was used, but failed to adequately describe the measured intensities, especially in RbFeCl3. The observed anomalies, such as anisotropic azimuthal intensity distribution, were attributed to long-range dipolar interactions.
Article
Materials Science, Multidisciplinary
Naoto Yokoi, Eiji Saitoh
Summary: The dynamics of multimode magnons affected by demagnetizing fields have been discussed using a Hamiltonian approach. Inter-mode correlation of magnons was found to spontaneously form, suppressing transverse magnetization dynamics and resulting in depolarization correlation (DPC) of magnons, which may exist in equilibrium distribution at finite temperatures.
Article
Materials Science, Multidisciplinary
Bin Gao, Tong Chen, Chong Wang, Lebing Chen, Ruidan Zhong, Douglas L. Abernathy, Di Xiao, Pengcheng Dai
Summary: Study of spin waves in a honeycomb-lattice antiferromagnet with a zigzag antiferromagnetic ground state revealed symmetry-protected Dirac points, providing insight into the magnetic interactions in honeycomb-lattice magnets and Kitaev quantum spin liquid candidates.
Article
Mathematics, Applied
Zakia Rahim, Muhammad Adnan, Anisa Qamar
Summary: The study utilizes the quantum hydrodynamic model to investigate the nonlinear propagation of small amplitude magnetosonic solitons and their chaotic motions in quantum plasma. The research demonstrates that various plasma parameters significantly affect the soliton characteristics, with an increase in quantum statistics, magnetization energy, exchange effects, and spin polarization density ratio leading to changes in soliton properties. Additionally, the presence of external periodic perturbations transforms periodic solitonic behavior into quasiperiodic and chaotic oscillations.
Article
Materials Science, Multidisciplinary
Ritwik Mondal, Levente Rozsa
Summary: The spin-wave spectrum in ferromagnets and two-sublattice antiferromagnets in the presence of inertial effects is calculated in this study. It is found that the hybridization between precession and nutation spin waves leads to the renormalization of frequencies, group velocities, effective gyromagnetic ratios, and effective damping parameters. Possible ways of distinguishing between inertial dynamics and similar effects explained within conventional models are discussed.
Article
Physics, Multidisciplinary
Kh Zakeri, A. Hjelt, I. Maznichenko, P. Buczek, A. Ernst
Summary: This study investigates the lifetime of quantum confined magnon modes in ultrathin layered magnetic structures. The findings show that quantum confined magnons exhibit nonlinear decay rates, contrary to classical dynamics assumptions. By combining experimental results and linear-response density-functional calculations, a quantitative explanation for this nonlinear damping effect is provided. These results offer new insights into the decay mechanism of spin excitations in ultrathin films and multilayers, as well as pave the way for tuning the dynamical properties of such structures.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Qi-Hui Chen, Fei-Jie Huang, Yong-Ping Fu
Summary: We investigate the magnon excitations and their interactions in honeycomb antiferromagnets with the Dzyaloshinskii-Moriya interaction. The classical ground state of the system is noncollinear antiferromagnetic order under an applied magnetic field, so considering the interactions between magnons is crucial. We find an exact solution of the bosonic Bogoliubov-de Gennes Hamiltonian and analytically study the topological properties and damping effects of the magnon bands.
Article
Materials Science, Multidisciplinary
Mai Kameda, Gerrit E. W. Bauer, Joseph Barker
Summary: In this study, we observed a rotonlike excitation, known as a gapped local minimum, in the amorphous ferromagnet Co4P. Previous theories failed to explain this feature, but we overcame these limitations by combining the reverse Monte Carlo method and large-scale atomistic spin simulations. We found that the rotonlike feature is actually gapless, contrary to previous studies, and can be attributed to amorphous umklapp scattering caused by residual structural order.
Article
Materials Science, Multidisciplinary
Yuying Yang, Mengmeng Wei, Wei Qin
Summary: The study found that photo-magnetic coupling was generated through direct spin-photon interactions in organic ferromagnetic crystals. Spin angular momentum can be directly transferred from the polarized spin of an electron to a photon, altering the polarized state of light. When the temperature exceeds the Curie temperature of organic ferromagnets, spontaneous spin polarization is not generated, leading to the disappearance of photo-magnetic coupling.
APPLIED MATERIALS TODAY
(2021)
Article
Physics, Multidisciplinary
A. Scheie, Pontus Laurell, P. A. McClarty, G. E. Granroth, M. B. Stone, R. Moessner, S. E. Nagler
Summary: The study reveals gadolinium as a Dirac magnon material with nodal lines and planes, showing nontrivial Berry phases and topological surface modes for the nodal lines. The origin and effect of nodal planes are characterized by a topological invariant. These results suggest a highly nontrivial topology, which is common to hexagonal close packed ferromagnets, with potential implications for other similar systems.
PHYSICAL REVIEW LETTERS
(2022)
Article
Multidisciplinary Sciences
Daniel G. Mazzone, Derek Meyers, Yue Cao, James G. Vale, Cameron D. Dashwood, Youguo Shi, Andrew J. A. James, Neil J. Robinson, Jiaqi Lin, Vivek Thampy, Yoshikazu Tanaka, Allan S. Johnson, Hu Miao, Ruitang Wang, Tadesse A. Assefa, Jungho Kim, Diego Casa, Roman Mankowsky, Diling Zhu, Roberto Alonso-Mori, Sanghoon Song, Hasan Yavas, Tetsuo Katayama, Makina Yabashi, Yuya Kubota, Shigeki Owada, Jian Liu, Junji Yang, Robert M. Konik, Ian K. Robinson, John P. Hill, Desmond F. McMorrow, Michael Forst, Simon Wall, Xuerong Liu, Mark P. M. Dean
Summary: Using ultrafast resonant inelastic X-ray scattering, we have shown that femtosecond laser pulses can excite transient magnons at large wavevectors in gapped antiferromagnets, persisting for several picoseconds. Our work suggests that materials with isotropic magnetic interactions are preferred for achieving rapid manipulation of magnetism.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Materials Science, Multidisciplinary
Thorbjorn Skovhus, Thomas Olsen
Summary: In this study, time-dependent density functional theory was used to calculate the magnetic phonon dispersion of bcc Cr and Cr2O3. It was found that the adiabatic local density approximation had a good qualitative agreement with the dispersion of Cr2O3, but overestimated the magnon velocity and bandwidth. For bcc Cr, a sharp phonon mode and a higher energy collective mode were observed.
Article
Physics, Applied
Khalil Zakeri, Tobias Engelhardt, Matthieu Le Tacon, Thomas Wolf
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
(2018)
Article
Physics, Applied
Khalil Zakeri
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS
(2018)
Review
Physics, Condensed Matter
Pawel Buczek, Stefan Thomas, Alberto Marmodoro, Nadine Buczek, Xabier Zubizarreta, Martin Hoffmann, Timofey Balashov, Wulf Wulfhekel, Khalil Zakeri, Arthur Ernst
JOURNAL OF PHYSICS-CONDENSED MATTER
(2018)
Article
Physics, Multidisciplinary
H. J. Qin, S. Tsurkan, A. Ernst, Kh Zakeri
PHYSICAL REVIEW LETTERS
(2019)
Review
Physics, Condensed Matter
Khalil Zakeri
JOURNAL OF PHYSICS-CONDENSED MATTER
(2020)
Article
Physics, Multidisciplinary
Khalil Zakeri, Huajun Qin, Arthur Ernst
Summary: The article discusses the formation and effects of magnonic surface and interface states in layered ferromagnets, showcasing experimental examples and suggesting potential characteristics. The authors also propose the possibility of customizing these states through artificial fabrication.
COMMUNICATIONS PHYSICS
(2021)
Article
Physics, Multidisciplinary
Kh Zakeri, A. Hjelt, I. Maznichenko, P. Buczek, A. Ernst
Summary: This study investigates the lifetime of quantum confined magnon modes in ultrathin layered magnetic structures. The findings show that quantum confined magnons exhibit nonlinear decay rates, contrary to classical dynamics assumptions. By combining experimental results and linear-response density-functional calculations, a quantitative explanation for this nonlinear damping effect is provided. These results offer new insights into the decay mechanism of spin excitations in ultrathin films and multilayers, as well as pave the way for tuning the dynamical properties of such structures.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Khalil Zakeri, Janek Wettstein, Christoph Suergers
Summary: The authors demonstrate that in Bi2Se3, collective charge excitations can initiate spin-dependent electron scattering at the surface, revealing new possibilities for generating spin-polarized currents or analyzing electron spins in topological insulators. The observed effect presents important implications for understanding spin polarization of photo-excited electrons and inspires new ideas for utilizing plasmonic excitations in spin-plasmonics.
COMMUNICATIONS PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Dominik Rau, Jasmin Jandke, Fang Yang, Wulf Wulfhekel, Christophe Berthod, Khalil Zakeri
Summary: Spin-orbit coupling (SOC) is a fundamental physical interaction that describes the coupling between electron spin and orbital motion. In this study, we performed spectroscopy experiments on a FeSe monolayer on strontium titanate, a two-dimensional high-temperature superconductor, and found that the scattering cross-section is spin dependent. We showed that the SOC in this system is strong and may have important implications for the electronic structures and the mechanism of superconductivity.
Article
Materials Science, Multidisciplinary
Khalil Zakeri, Dominik Rau, Janek Wettstein, Markus Doettling, Jasmin Jandke, Fang Yang, Wulf Wulfhekel, Joerg Schmalian
Summary: Using high-resolution electron spectroscopy, the dynamic charge response of FeSe/SrTiO3 heterostructures is studied, revealing the existence of a charge depletion layer at the interface. This depletion layer, accompanied by a significant charge transfer, results in a renormalization of SrTiO3 energy bands and substantial band bending at the interface. This discovery opens up possibilities for designing novel 2D superconductors through interface engineering, which is expected to occur at the interface of many vdW monolayers and dielectric oxides.
Article
Materials Science, Multidisciplinary
Khalil Zakeri, Christophe Berthod
Summary: This paper extends the theory of low-energy electron scattering by including spin-orbit coupling. The impact of this interaction on the scattering cross section is discussed, particularly for a spin-polarized electron beam scattered from nonmagnetic surfaces with strong spin-orbit coupling. An expression for the scattering cross section is derived under certain assumptions, which can be used for numerical calculations of spin-polarized spectra recorded by spin-polarized high-resolution electron energy-loss spectroscopy experiments.
Meeting Abstract
Radiology, Nuclear Medicine & Medical Imaging
E. Aliotta, J. Hesse, E. Subashi, P. Scripes, M. Aristophanous, J. Mechalakos, L. Cervino, N. Tyagi, K. Zakeri, N. Lee
Article
Materials Science, Multidisciplinary
S. Abdizadeh, J. Abouie, Kh Zakeri
Article
Materials Science, Multidisciplinary
Jasmin Jandke, Fang Yang, Patrik Hlobil, Tobias Engelhardt, Dominik Rau, Khalil Zakeri, Chunlei Gao, Joerg Schmalian, Wulf Wulfhekel
Article
Materials Science, Multidisciplinary
S. Tsurkan, Kh Zakeri
Review
Physics, Multidisciplinary
Sebastian Mizera
Summary: This article discusses the mathematical properties and physical implications of scattering amplitudes, and traces these properties back to physics through simple scattering problems.
PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS
(2024)