arXiv subjects

Z. P. Hou

Publications and source records attributed to Z. P. Hou.

10 recordsLinked to original sources

arXiv2026

Enhanced electronic correlations and altermagnetic ground state of two-dimensional CsCr3Sb5 monolayers

Recently, layered corrected kagome metal CsCr3Sb5 have garnered significant attention attributed to its flat bands near the Fermi level (EF) and altermagnetic ground state [ Yi Liu et al., Nature 632, 1032 (2024)]. However, the van Hove singularities (vHSs) in bulk CsCr3Sb5 are far away from the EF, while an effective modulation of VHS toward the EF is essential for exploring intriguing electron transport properties. In this work, using first-principles calculations, we investigate electronic structures of two-dimensional (2D) Cr3Sb5 and CsCr3Sb5 monolayers which may be mechanically exfoliated from bulk materials. Notably, it is revealed that both flat bands and vHSs simultaneously reside in close proximity to the EF in Cr3Sb5 monolayer, signifying enhanced electronic correlations. Importantly, a tensile strain further shifts the incipient flat bands and vHSs of two monolayers simultaneously to the vicinity of the EF, suggesting strain tunable electronic correlations and concomitant quantum effects. Furthermore, altermagnetic ground state is also revealed due to retained mirror symmetry between two sublattices in these two monolayers. Thus, this work advances understanding and modulations of electronic properties of 2D CsCr3Sb5 monolayers, strengthening their great potential for exploring unconventional quantum phenomena and altermagnetism.

cond-mat.mtrl-sci↗

arXiv2024

Controllable magnon frequency comb in synthetic ferrimagnets

Magnon frequency comb provides opportunities for exploring magnon nonlinear effects and measuring the transmission magnon frequency in magnets, whose controllability becomes vital for modulating the operating frequency and improving the measurement accuracy. Nevertheless, such controllable frequency comb remains to be explored. In this work, we investigate theoretically and numerically the skyrmion-induced magnon frequency comb effect generated by interaction between the magnon excitation mode and skyrmion breathing mode in synthetic ferrimagnets. It is revealed that both the skyrmion breathing mode and the magnon frequency gap closely depend on the net angular momentum δs, emphasizing the pivotal role of δs as an effective control parameter in governing the comb teeth. With the increase of δs, the skyrmion size decreases, which results in the enlargement of the breathing frequency and the distance between the comb teeth. Moreover, the dependences of the magnon frequency gap on δs and the inter-layer coupling allow one to modulate the comb lowest coherent frequency via structural control. Consequently, the coherent modes generated by the comb may range from gigahertz to terahertz frequencies, serving as a bridge between microwave and terahertz waves. Thus, this work represents a substantial advance in understanding the magnon frequency comb effect in ferrimagnets.

physics.app-ph↗

arXiv2023

Optical-controlled ultrafast dynamics of skyrmion in antiferromagnets

Optical vortex, a light beam carrying orbital angular momentum (OAM) has been realized in experiments, and its interactions with magnets show abundant physical characteristics and great application potentials. In this work, we propose that optical vortex can control skyrmion ultrafast in antiferromagnets using numerical and analytical methods. Isolated skyrmion can be generated/erased in a very short time ~ps by beam focusing. Subsequently, the OAM is transferred to the skyrmion and results in its rotation motion. Different from the case of ferromagnets, the rotation direction can be modulated through tuning the light frequency in antiferromagnets, allowing one to control the rotation easily. Furthermore, the skyrmion Hall motion driven by multipolar spin waves excited by optical vortex is revealed numerically, demonstrating the dependence of the Hall angle on the OAM quantum number. This work unveils the interesting optical-controlled skyrmion dynamics in antiferromagnets, which is a crucial step towards the development of optics and spintronics.

physics.optics↗

arXiv2022

Dynamics of hybrid magnetic skyrmion driven by spin-orbit torque in ferrimagnets

Magnetic skyrmions are magnetic textures with topological protection, which are expected to be information carriers in future spintronic devices. In this work, we propose a scheme to implement hybrid magnetic skyrmions (HMS) in ferrimagnets, and we study theoretically and numerically the dynamics of the HMS driven by spin-orbit torque. It is revealed that the skyrmion Hall effect depends on the skyrmion helicity and the net angular momentum (δs), allowing the effective modulation of the HMS motion through tuning Dzyaloshinskii-Moriya interaction and δs. Thus, the Hall effect can be suppressed through selecting suitable materials to better control the HMS motion. Moreover, Magnus force for finite δs suppresses the transverse motion and enhances the longitudinal propagation, resulting in the HMS dynamics in ferrimagnets faster than that in antiferromagnets.

physics.app-ph↗

arXiv2022

Spin-wave-driven skyrmion dynamics in ferrimagnets: Effect of net angular momentum

Searching for low-power-consuming and high-efficient methods for well controllable driving of skyrmion motion is one of the most concerned issues for future spintronic applications, raising high concern with an appreciated choice of magnetic media and driving scenario. In this work, we propose a novel scenario of spin wave driven skyrmion motion in a ferrimagnetic (FiM) lattice with the net angular momentum δs. We investigate theoretically the effect of both δs and the circular polarization of spin wave on the skyrmion dynamics. It is revealed that the momentum onto the skyrmion imposed by the excited spin wave can be partitioned into a ferromagnetic term plus an antiferromagnetic term. The ratio of these two terms and consequently the Hall angle of skyrmion motion can be formulated as the functions of δs, demonstrating the key role of δs as an effective control-parameter for the skyrmion motion. Moreover, the spin wave frequency dependent skyrmion motion is discussed, predicting the frequency enhanced skyrmion Hall motion. This work thus represents an essential contribution to understand the skyrmion dynamics in a FiM lattice.

physics.app-ph↗

arXiv2022

Handedness-filter and Doppler shift of spin waves in ferrimagnetic domain walls

Excitation and propagation of spin waves inside magnetic domain walls has received attention because of their potentials in spintronic and communication applications. Besides wave amplitude and frequency, spin-wave has its third character: handedness, whose manipulation is certainly of interest. We propose in this Letter that the handedness of low energy spin-wave excitations can be controlled by tuning the net angular momentum δs in a ferrimagnetic (FiM) domain wall, attributing to the inequivalent magnetic sublattices. The results indicate that the spin-wave dispersion depends on both δs and wave handedness. For a positive (negative) δs, a gapless dispersion is observed for the left-handed (righ-handed) spin waves, while a frequency gap appears for the right-handed (left-handed) spin waves. Thus a FiM wall could serve as a multifold filter of low energy spin-wave in which only spin waves with particular handedness can propagate. Furthermore, the energy consumption loss for spin-wave excitation in the wall is much lower than that inside the domain, while the group velocity is much faster too, demonstrating the advantages of domain walls serving as spin waveguides. Moreover, the current-induced spin-wave Doppler shift in the FiM wall is also revealed, and can be controlled by δs. This work unveils for the first time the interesting spin-wave dynamics in FiM domain walls, benefiting future spin-wave applications.

physics.app-ph↗

arXiv2021

Magnon-driven dynamics of frustrated skyrmion in synthetic antiferromagnets: Effect of skyrmion precession

A theoretical study on the interplay of frustrated skyrmion and magnons is useful for revealing new physics and future experiments design. In this work, we investigated the magnon-driven dynamics of frustrated skyrmion in synthetic antiferromagnets, focusing on the effect of skyrmion precession. It is theoretically revealed that the scattering cross section of the injected magnons depends on the skyrmion precession, which in turn effectively modulates the skyrmion Hall motion. Specifically, the Hall angle decreases as the precession speed increases, which is also verified by the atomistic micromagnetic simulations. Moreover, the precession speed and the Hall angle of the frustrated skyrmion depending on the magnon intensity and damping constant are simulated, demonstrating the effective suppression of the Hall motion by the skyrmion precession. This work provides a comprehensive understanding of the magnon-skyrmion scattering in frustrated magnets, benefiting future spintronic and magnonic applications.

physics.app-ph↗

arXiv2020

Dynamics of antiferromagnetic skyrmion in absence and presence of pinning defect

A theoretical study on the dynamics of an antiferromagnetic (AFM) skyrmion is indispensable for revealing the underlying physics and understanding the numerical and experimental observations. In this work, we present a reliable theoretical treatment of the spin current induced motion of an AFM skyrmion in the absence and presence of pinning defect. For an ideal AFM system free of defect, the skyrmion motion velocity as a function of the intrinsic parameters can be derived, based on the concept that the skyrmion profile agrees well with the 360 domain wall formula, leading to an explicit description of the skyrmion dynamics. However, for an AFM lattice containing a defect, the skyrmion can be pinned and the depinning field as a function of damping constant and pinning strength can be described by the Thiele approach. It is revealed that the depinning behavior can be remarkably influenced by the time dependent oscillation of the skyrmion trajectory. The present theory provides a comprehensive scenario for manipulating the dynamics of AFM skyrmion, informative for future spintronic applications based on antiferromagnets.

cond-mat.mtrl-sci↗

arXiv2018

Skyrmion crystals in frustrated Shastry-Sutherland magnets

The phase diagrams of the frustrated classical spin model with Dzyaloshinskii-Moriya (DM) interaction on the Shastry-Sutherland (S-S) lattice are studied by means of Monte Carlo simulation. For ferromagnetic next-nearest-neighboring (J2) interactions, the introduced exchange frustration enhances the effect of the DM interaction, which enlarges the magnetic field-range with the skyrmion lattice phase and increases the skyrmion density. For antiferromagnetic J2 interactions, the so-called 2q phase (two-sublattice skyrmion crystal) and the spin-flop phase are observed in the simulated phase diagram, and their stabilizations are closely dependent on the DM interaction and J2 interaction, respectively. The simulated results are qualitatively explained from the energy landscape, which provides useful information for understanding the intriguing phases in S-S magnets.

physics.app-ph↗

arXiv2015

New spin injection scheme based on spin gapless semiconductors: A first-principles study

Spin injection efficiency based on conventional and/or half-metallic ferromagnet/semiconductor is greatly limited by the Schmidt obstacle due to conductivity mismatch, here we proposed that by replacing the metallic injectors with spin gapless semiconductors can significantly reduce the conductive mismatch to enhance spin injection efficiency. By performing first principles calculations based on superlattice structure, we have studied the representative system of Mn2CoAl/semiconductor spin injector scheme. The results showed that a high spin polarization was maintained at the interface in systems of Mn2CoAl/Fe2VAl constructed with (100) interface and Mn2CoAl/GaAs with (110) interface, and the latter is expected to possess long spin diffusion length. Inherited from the spin gapless feature of Mn2CoAl, a pronounced dip was observed around the Fermi level in the majority-spin density-of-states in both systems, suggesting fast transport of the low-density carriers.

cond-mat.mtrl-sci↗