arXiv subjects

Haiming Dong

Publications and source records attributed to Haiming Dong.

4 recordsLinked to original sources

arXiv2025

Ultrafast manipulation of magnetic skyrmions by microwave fields

We theoretically investigate the inertial dynamics of magnetic skyrmions driven by circularly polarized microwave-induced inverse Faraday effect (MIFE). By incorporating an inertial mass term into the Thiele equation and analytically deriving the microwave-induced magnetic fields and forces, we demonstrate fundamentally distinct dynamical regimes under continuous-wave (CW) versus pulsed excitation. Skyrmion inertia qualitatively transforms trajectories from smooth spirals to polygonal orbits under continuous driving, while enabling sustained post-pulse gyration that reveals the system's intrinsic relaxation dynamics. The handedness of the trajectory is determined by the topological charge and circularly polarized microwave (CPM) helicity: a left-circularly polarized (LCP) CPM attracts skyrmions toward the beam center, while a right-circularly polarized (RCP) CPM repels them. Systematic parameter analysis reveals how Gilbert damping, the intensity and frequency of CPM, and skyrmion mass control the transition between oscillatory and overdamped dynamical phases. Our work identifies inertia, topological charge, and CPM helicity as essential factors in ultrafast skyrmion manipulation and proposes a novel method for designing topological spin textures.

cond-mat.mtrl-sci↗

arXiv2025

Tilted chiral spin textures in confined nanostructures with in-plane magnetic anisotropy

We demonstrate that nanoconfinement effects and in-plane magnetic anisotropy (IMA) can lead to tilted chiral spin textures in magnetic nanostructures, based on the analysis and simulation of theoretical models of micromagnetism. The tilted skyrmions are induced in confined nanoscale magnets with IMA under perpendicular magnetic fields. The chiral magnetic structures depend significantly on the size of the nanostructures. A controlled string of periodic skyrmion states emerges within the central magnetic domain wall, which can be tuned by the steady magnetic fields and the size of the nanostructures. Non-trivial topological states with non-integer topological charges are achieved by tuning the magnetic fields or the sizes of the nanostructures. Importantly, the periodic switching between the trivial and the non-trivial topological configurations is realized using an alternating magnetic field. Our study reveals an important mechanism for controlling novel skyrmion states via nanoconfinement effects and the IMA in magnetic nanostructures, and also provides a new approach for the development of magnetic field-modulated spin nanodevices.

cond-mat.mes-hall↗

arXiv2024

Ultrafast manipulations of nanoscale skyrmioniums

The advancement of next-generation magnetic devices depends on fast manipulating magnetic microstructures on the nanoscale. A universal method is presented for rapidly and reliably generating, controlling, and driving nano-scale skyrmioniums, through high-throughput micromagnetic simulations. Ultrafast switches are realized between skyrmionium and skyrmion states and rapidly change their polarities in monolayer magnetic nanodiscs by perpendicular magnetic fields. The transition mechanism by alternating magnetic fields differs from that under steady magnetic fields. New skyrmionic textures, such as flower-like and windmill-like skyrmions, are discovered. Moreover, this nanoscale skyrmionium can move rapidly and stably in nanoribbons using weaker spin-polarized currents. Explicit discussions are held regarding the physical mechanisms involved in ultrafast manipulations of skyrmioniums. This work provides further physical insight into the manipulation and applications of topological skyrmionic structures for developing low-power consumption and nanostorage devices.

cond-mat.mes-hall↗

arXiv2011

Terahertz relativistic spatial solitons in doped graphene metamaterials

We propose an electrically tunable graphene-based metamaterial showing a large nonlinear optical response at THz frequencies, which we calculate analytically for the first time to our knowledge and arises from the intraband current. The structure sustains a novel type of stable two-dimensional spatial solitary wave, a relativistic version of the Townes soliton. These results can be also applied to any material exhibiting a conical dispersion with massless Dirac fermions.

physics.optics↗