Article
Physics, Applied
Yang Yang, Yahui Ji, Chenye Zhang, Tianxiang Nan
Summary: In this study, the effect of surface acoustic waves (SAWs) on the motion of magnetic skyrmions is investigated using micromagnetic simulations. Different types and directions of SAWs generate different magnetoelastic effective fields, leading to the movement of skyrmions. Increasing the amplitude and magnetoelastic coupling constants of the acoustic wave, as well as reducing the wavelength, enhances the skyrmion motion velocity. The trajectory of skyrmion motion can be controlled through the design of the magnetic film geometry. Interestingly, in a circular magnetic film, skyrmions driven by SH waves exhibit clockwise or counterclockwise movement depending on the sign of topological charges. These results provide an energy efficient approach for driving skyrmion dynamics and have implications for low-power spintronics.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Yu Wang, Takahiro Shimada, Jie Wang, Takayuki Kitamura, Hiroyuki Hirakata
Summary: This study demonstrates the rectilinear motion of individual skyrmions in temperature gradients using a temperature-related phase field model and reveals that the energy imbalance induced by temperature gradients drives the motion of skyrmions. A kinematic equation is proposed to describe the motion of skyrmions in temperature gradients.
Article
Physics, Multidisciplinary
Z. Jin, T. T. Liu, Y. Liu, Z. P. Hou, D. Y. Chen, Z. Fan, M. Zeng, X. B. Lu, X. S. Gao, M. H. Qin, J-M Liu
Summary: This theoretical study investigates the effect of skyrmion helicity oscillation on the magnon-driven dynamics of frustrated skyrmions. The results show that the oscillation effectively suppresses Hall motion and modulates the scattering cross-section of injected magnons, providing a comprehensive understanding of magnon-skyrmion scattering in frustrated magnets.
NEW JOURNAL OF PHYSICS
(2022)
Article
Multidisciplinary Sciences
R. Brearton, L. A. Turnbull, J. A. T. Verezhak, G. Balakrishnan, P. D. Hatton, G. van der Laan, T. Hesjedal
Summary: Magnetic skyrmions are topologically non-trivial magnetic moments that form lattices in helimagnetic materials, showing promise as efficient information carriers. The skyrmion Hall angle, which measures the deviation of skyrmion motion from the driving force, can be determined using reciprocal space techniques. Skyrmions experience deflection under a shear drive, leading to an additional sideways motion known as the skyrmion hall effect.
NATURE COMMUNICATIONS
(2021)
Article
Physics, Multidisciplinary
S. H. Guan, Y. Yang, Z. Jin, T. T. Liu, Y. Liu, M. H. Qin
Summary: The study investigates the dynamics of skyrmions in antiferromagnets driven by circularly polarized spin waves and proposes a method to suppress Hall motion. It is found that using two circularly polarized spin waves with opposite chirality allows skyrmions to move straightly and the speed depends on the parameters of the spin waves and system. Two depinning behaviors related to defect strengths are observed, indicating the potential for precise modulation of skyrmion dynamics in memory device design.
FRONTIERS IN PHYSICS
(2021)
Article
Engineering, Electrical & Electronic
Ilya O. Gorshkov, Roman V. Gorev, Maksim V. Sapozhnikov, Oleg G. Udalov
Summary: In this study, we investigate the control of skyrmions in an artificial ultrathin magnetic film with perpendicular anisotropy. By numerically simulating the motion of skyrmions induced by the spatial gradient of the Dzyaloshinskii-Moriya interaction (DMI) strength, we demonstrate that creating a DMI gradient is an efficient way to manipulate skyrmions. Furthermore, experimentally achievable DMI gradients can be as effective as spin-polarized electric currents, but with a weaker skyrmion Hall effect. These DMI gradients can be created by applying mechanical strain in a ferroelectric-ferromagnetic hybrid system, providing an alternative approach for skyrmion manipulation.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Rohollah Khoshlahni, Serban Lepadatu, Majid Kouhi, Majid Mohseni
Summary: This paper investigates the dynamics of a magnetic skyrmion induced by linear and circular surface acoustic waves in antiferromagnetic (AFM) systems. The motion of the skyrmion is determined by the force and torque applied by the surface waves, taking into account the conservation of linear and angular momenta. The dynamics of the skyrmion are described by a coupled nonlinear differential equation, with no Hall effect observed in linear waves and a ratchet motion observed in circular waves.
Article
Materials Science, Multidisciplinary
Markus Weissenhofer, Ulrich Nowak
Summary: Magnetic skyrmions are promising for spintronic applications, but face challenges like the skyrmion Hall effect and inefficient detection. This study investigates the current-driven and Brownian dynamics of skyrmions in ferrimagnetic materials with a compensation point. Results show a nonmonotonic temperature dependence of the velocities and the diffusion coefficient, with a strong enhancement at the angular momentum compensation temperature. These findings provide a new pathway for the efficient manipulation of skyrmion dynamics via temperature.
Article
Nanoscience & Nanotechnology
Chao Chen, Tao Lin, Jianteng Niu, Yiming Sun, Liu Yang, Wang Kang, Na Lei
Summary: This study proposes controlling magnetic skyrmions using electric-field-excited surface acoustic waves in neuromorphic computing device structures. The micromagnetic simulations show that the number of created skyrmions increases with the amplitude of the surface acoustic waves. The efficiency of skyrmion creation is systematically investigated with a wide range of magnetic parameters, and the optimal values are determined. The functionalities of short-term plasticity and long-term potentiation are demonstrated using a sequence of surface acoustic waves with different intervals.
Article
Physics, Applied
Chao Chen, Dahai Wei, Liang Sun, Na Lei
Summary: We suppress the skyrmion Hall effect and enable the motion of skyrmions along the driven current by constructing artificial tracks using standing surface acoustic waves (SSAWs). Through micro-magnetic simulations and an analytical model, we identify the key parameters for eliminating the skyrmion Hall effect and demonstrate a reconfigurable multichannel skyrmion racetrack.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
A. Sudeepthi, A. Nath, L. Y. Yeo, A. K. Sen
Summary: This study investigates the coalescence of droplets in a two-phase system in microwells driven by surface acoustic waves (SAWs) and elucidates the physics behind the phenomenon through a scaling analysis of relevant forces. The influence of input SAW power and droplet size on film drainage time is explored, and criteria for the onset of coalescence are derived. The study demonstrates the possibility of driving concurrent coalescence of multiple droplets, with potential applications in demulsification and sample/reagent mixing within microwells for biochemical assays.
Article
Materials Science, Multidisciplinary
Sujit Panigrahy, Sougata Mallick, Joao Sampaio, Stanislas Rohart
Summary: We study the behavior of magnetic skyrmions in synthetic antiferromagnets with interlayer coupling. Results show that the coupled skyrmions reach a stationary regime with a spatial separation due to the opposite gyrovector in the two layers. A transient regime with finite acceleration and limited time response is observed. The phenomenon is quantitatively described using two coupled Thiele equations.
Article
Materials Science, Multidisciplinary
Kyoung-Woong Moon, Seungmo Yang, Tae-Seong Ju, Changsoo Kim, Byoung Sun Chun, Sungkyun Park, Chanyong Hwang
Summary: Magnetic skyrmions, as topological swirling spin textures, have attracted much attention in spintronics due to their robustness rooted in their topological nature. This study presents a method to generate skyrmions by driving stripe instability, regardless of other material parameters, and applicable to generic magnetic films with perpendicular magnetic anisotropy. The work will facilitate the development of skyrmion-based devices by offering a general method for controlling a large skyrmion population.
NPG ASIA MATERIALS
(2021)
Article
Physics, Multidisciplinary
Satoru Hayami
Summary: The study investigates the emergence of a magnetic bubble crystal, a type of multiple-Q state composed of collinear sinusoidal waves, in a centrosymmetric itinerant electron system at finite temperatures. By conducting a large-scale numerical simulation and analyzing the effective spin model, the researchers identified the minimal key ingredients for inducing the finite-temperature transition between the skyrmion crystal and the bubble crystal. The results demonstrate the significant role played by the synergy between multiple-spin interaction and magnetic anisotropy in the phase transition.
NEW JOURNAL OF PHYSICS
(2021)
Article
Multidisciplinary Sciences
Kang Wang, Yiou Zhang, Vineetha Bheemarasetty, Shiyu Zhou, See-Chen Ying, Gang Xiao
Summary: This research demonstrates a skyrmion true random number generator with magnetic field and spin current as control parameters by studying the local dynamics of skyrmions interacting with pinning sites.
NATURE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Wuzhang Fang, Aldo Raeliarijaona, Po-Hao Chang, Alexey A. Kovalev, Kirill D. Belashchenko
Summary: In this study, realizations of spirals and skyrmions in two-dimensional antiferromagnets with a triangular lattice on an inversion-symmetry-breaking substrate were investigated. The adsorption of transition-metal atoms on monolayers of MoS2, WS2, or WSe2 was studied to obtain interaction parameters using first-principles calculations. Results showed that even weak Dzyaloshinskii-Moriya interactions can lead to the appearance of skyrmion lattices, but their stability may be hindered by magnetic anisotropy.
PHYSICAL REVIEW MATERIALS
(2021)
Correction
Materials Science, Multidisciplinary
K. D. Belashchenko, Alexey A. Kovalev, M. van Schilfgaarde
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Applied
Utkan Guengoerdue, Alexey A. Kovalev
Summary: The aim of this tutorial is to provide an introduction to the realization of Majorana bound states (MBSs) in condensed matter systems with magnetic textures. The tutorial discusses the Kitaev chain model and its two-dimensional generalization, emphasizing the relation between topological superconductivity and the realization of MBS. It also explores how spinless fermions can be realized in physical systems and how magnetic textures can induce synthetic spin-orbit interactions to stabilize MBS. The tutorial further demonstrates the use of skyrmions to stabilize MBS and perform braiding operations.
JOURNAL OF APPLIED PHYSICS
(2022)
News Item
Physics, Multidisciplinary
Alexey A. Kovalev
Summary: Experiments with chiral magnets are crucial for understanding the transformations between different skyrmionic states, which are essential for the development of magnetic memory and logic applications.
Article
Materials Science, Multidisciplinary
K. D. Belashchenko, G. G. Baez Flores, W. Fang, A. A. Kovalev, M. van Schilfgaarde, P. M. Haney, M. D. Stiles
Summary: Spin-accumulation and spin-current profiles in a disordered Pt film subjected to an in-plane electric current are calculated using the nonequilibrium Green's function approach. The results show qualitative differences near the surfaces compared to the widely used spin-diffusion model, even with modified boundary conditions. The effective spin-diffusion length for transverse spin transport is significantly different from its longitudinal counterpart, resembling the mean-free path. Orbital accumulation in the Pt film is only significant near the surfaces and penetrates into the bulk as a secondary effect induced by the spin accumulation.
Article
Materials Science, Multidisciplinary
Edward Schwartz, Hamed Vakili, Moaz Ali, Alexey A. Kovalev
Summary: This study investigates the interplay between vorticity and spin currents in an easy-plane magnet, showing the generation of transverse spin currents accompanying the flow of vorticity, known as the spin Hall effect of vorticity. The research also examines the effect across the BKT transition and highlights the role of dissipation and spin nonconservation in the transition from spin superfluidity to diffusive spin transport. The results of this study pave the way for low power computing devices based on vorticity and spin flows that can propagate over long distances.
Article
Physics, Multidisciplinary
Edward Schwartz, Bo Li, Alexey A. Kovalev
Summary: This study proposes the use of Hall response of topological defects to identify the BKT transition in a two-dimensional magnetic insulator. Numerical simulations show the transition from spin superfluidity to conventional spin transport.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Physics, Multidisciplinary
Utkan Gungordu, J. P. Kestner
Summary: This paper presents a general method for obtaining truly smooth pulses in quantum computers to suppress the effects of noise, by parameterizing the Hamiltonian using a neural network.
PHYSICAL REVIEW RESEARCH
(2022)
Correction
Materials Science, Multidisciplinary
K. D. Belashchenko, Alexey A. Kovalev, M. van Schilfgaarde
Article
Materials Science, Multidisciplinary
Shane Sandhoefner, Aldo Raeliarijaona, Rabindra Nepal, Dalton Snyder-Tinoco, Alexey A. Kovalev
Summary: This paper presents a theory of generating skyrmions and antiskyrmions using magnetic field and charge current pulses, showing that topological defects can be created at edges and boundaries between regions with different DMI. Both perpendicular and in-plane versions of skyrmions and antiskyrmions are considered, with the presence of magnetization twists near edges or boundaries leading to the generation of topological defects. The study demonstrates that magnetic excitations localized near boundaries can develop instabilities under the influence of magnetic field and charge current pulses, resulting in the formation of skyrmions or antiskyrmions. Furthermore, the skyrmion and antiskyrmion Hall effects allow for pushing the topological defects away from boundaries through proper current direction, facilitating their generation.
Article
Materials Science, Multidisciplinary
David W. Kanaar, Sidney Wolin, Utkan Gungordu, J. P. Kestner
Summary: This paper demonstrates how to perform single-qubit and controlled-Z gates in a linear chain of three silicon spin qubits, as well as improve the CZ gate robustness against charge noise and pulse length error using a two-tone pulse shaping method. The robust pulse maintains a fidelity of 99.99% at 3.5% fluctuations in exchange or pulse amplitude, a significant improvement over uncorrected pulses.
Article
Materials Science, Multidisciplinary
Bo Li, Alexey A. Kovalev
Summary: This study explores spin superfluid transport in exchange interaction-dominated three-sublattice antiferromagnets, identifying a power-law spatial decay signature of spin superfluidity and suggesting iron jarosites as promising material candidates for realizing the proposal. The system approximately holds a U(1)-rotation symmetry even with additional corrections from interactions or anisotropies.
Article
Physics, Multidisciplinary
Bo Li, Alexey A. Kovalev
PHYSICAL REVIEW LETTERS
(2020)
Article
Optics
R. K. L. Colmenar, Utkan Gungordu, J. P. Kestner
Article
Materials Science, Multidisciplinary
Utkan Gungordu, J. P. Kestner
