arXiv subjects

Xiyin Ye

Publications and source records attributed to Xiyin Ye.

9 recordsLinked to original sources

arXiv2026

Scattering-Induced Magnon Layer-Hall Transport beyond Band Geometry

The layer Hall effect has been exclusively attributed to layer-locked Berry curvature, posing a fundamental barrier to its realization in conventional magnets. Here we report a fundamentally distinct layer Hall effect for bosonic excitations, i.e., magnons, which originates solely from non-reciprocal dipolar scattering at heterointerfaces, thereby decoupling the phenomenon from geometric-phase mechanisms. Using a microscopic scattering theory, we demonstrate that a longitudinal temperature gradient drives opposite transverse thermal Hall currents in a nanowire atop a magnetic film, with the direction fully reconfigurable by the applied magnetic field. The effect yields a significant Hall angle of $\sim 6^{\circ}$ in conventional magnetic heterostructures, eliminating the need for topological engineering. Our findings establish a scattering-driven paradigm for layer Hall effect, extendable to ferrons and polar phonons, and predict a Hall response that is readily detectable in conventional magnetic heterostructures.

cond-mat.mes-hall↗

arXiv2026

Ultrastrong magnon-photon coupling in superconductor/antiferromagnet/superconductor heterostructures at terahertz frequencies

We predict the realization of ultrastrong coupling between magnons of antiferromagnets and photons in superconductor/antiferromagnet/superconductor heterostructures at terahertz frequencies, from both quantum and classical perspectives. The hybridization of the two magnon modes with photons strongly depends on the applied magnetic field: at zero magnetic field, only a single antiferromagnetic mode with a lower frequency couples to the photon, forming a magnon-polariton, while using a magnetic field activates coupling for both antiferromagnetic modes. The coupling between magnon and photon is ultrastrong with the coupling constant $\sim$ 100 GHz exceeding 10% of the antiferromagnetic resonant frequency. The superconductor modulates the spin of the resulting magnon-polaritons and the group velocity, achieving values amounting to several tenths of the speed of light, which promises strong tunability of magnon transport in antiferromagnets by superconductors.

cond-mat.supr-con↗

arXiv2026

Frequency Comb of Electric-Polarization Waves

Frequency combs are a spectrum of equally spaced frequency components with very high time-frequency accuracy, which have been widely used in the optical and microwave frequency ranges. We propose the realization of a frequency comb operating at the terahertz regime in terms of the nonlinear dynamics of electric-polarization waves, or ferrons as their quanta, in the ferroelectric materials. The efficiency of the frequency comb of the electric-polarization waves is exactly proportional to the static electric polarization carried by the ferron modes, which thereby offers new opportunities for the direct observation and application of the intrinsic properties of ferrons.

cond-mat.mes-hall↗

arXiv2026

Ferron-Polaritons in Superconductor/Ferroelectric/Superconductor Heterostructures

We predict the formation of ferron-polariton - a hybrid light-matter quasiparticle arising from the coupling between collective ferroelectric excitations (ferrons) and Swihart photons in a superconductor/ferroelectric/superconductor heterostructure. The coupling provides direct evidence for ferrons and reaches the ultrastrong-coupling regime, with a spectral gap in the terahertz range, orders of magnitude larger than those in magnetic analogues, reflecting the superior strength of electric dipole interactions. Our work establishes superconductor-ferroelectric heterostructures as a novel platform for exploring extreme light-matter coupling and for developing high-speed, ferroelectric-based quantum technologies at terahertz frequencies.

cond-mat.supr-con↗

arXiv2025

Magnon Correlation Enables Spin Injection, Dephasing, and Transport in Canted Antiferromagnets

Thermal and electrical injection and transport of magnon spins in magnetic insulators is conventionally understood by the non-equilibrium population of magnons. However, this view is challenged by several recent experiments in noncollinear antiferromagnets, which urge a thorough theoretical investigation at the fundamental level. We find that the magnon spin in antiferromagnets is described by a matrix, so even when the diagonal terms -- spins carried by population -- vanish, the off-diagonal correlations transmit magnon spins. Our quantum theory shows that a net spin-flip of electrons in adjacent conductors creates quantum coherence between magnon states, which transports magnon spins in canted antiferromagnets, even without a definite phase difference between magnon modes in the incoherent process. It reveals that the pumped magnon correlation is not conserved due to an intrinsic spin torque, which causes dephasing and strong spatial spin oscillations during transport; both are enhanced by magnetic fields. Spin transfer to proximity conductors can cause extrinsic dephasing, which suppresses spin oscillations and thereby gates spin transport.

cond-mat.mes-hall↗

arXiv2025

Chiral Locking of Magnon Flow and Electron Spin Accumulation in Their Near-Field Radiative Spin Transfer

We report a non-contact mechanism for directional injection of magnons in magnetic films when driven by a spin accumulation $\pmbμ_s$ of electrons of a nearby metallic layer, governed by the long-range dipolar coupling between magnons and electron spins, which spontaneously generates a magnon current ${\bf J}_m$ flowing in the film plane. Crucially, in such near-field radiative spin transfer, the magnon flow ${\bf J}_m$ is always perpendicular to the spin accumulation $\pmbμ_s$, showing a universal chiral locking relation. The spin injection is efficient even when $\pmbμ_s$ is parallel to the magnetization, a feature breaking the limitation of the spin transfer by contact exchange interaction. Our findings reveal the critical role of dipolar chirality in driving the magnon thermal current and paving the way for the functional design of magnonic devices based on near-field radiative spin transfer.

cond-mat.mes-hall↗

arXiv2025

Spin Quenching and Transport by Hidden Dzyaloshinskii-Moriya Interactions

Explicit interactions, \textit{e.g.}, dipolar and exchange couplings, usually govern magnetization dynamics. Some interactions may be hidden from the global crystal symmetry. We report that in a large class of \textit{uniaxial} antiferromagnets, a \textit{hidden} Dzyaloshinskii-Moriya interaction with retaining global inversion symmetry quenches the spin of magnon along the Néel vector ${\bf n}$, thus forbidding its angular-momentum flow. Some magnon spins, termed ``nodal" and ``corner" spins, survive when they distribute \textit{singularly} at the hot spots, i.e., high-symmetric degeneracy points in the Brillouin zone, and are protected by crystal symmetries. The biased magnetic field along ${\bf n}$ broadens such distributions, allowing bulk spin transport with unique signatures in the magnetic field and temperature dependencies. This explains recent experiments and highlights the role of hidden interaction.

cond-mat.mes-hall↗

arXiv2024

Enhancement of Magnon Transport by Superconductor Meissner Screening

Recent experiments observe the spin-wave-Meissner-current modes in ferromagnetic insulator-superconductor heterostructures, in which the coherently excited spin waves seemingly do not decay as usual beneath the superconductor strip [Borst et al., Science 382, 430 (2023)]. We interpret this phenomenon by demonstrating that the stray magnetic field emitted by the magnetization dynamics is reflected, focused, and enhanced inside the ferromagnet by the supercurrent induced in the superconductor, such that the group velocity of spin waves is strongly enhanced. Analytical and numerical calculations based on this model predict that the coherent transport of magnons is enhanced by close to 500% for yttrium iron garnet capped by superconducting NbN with a decay length exceeding millimeters. Our finding may augment the performance of magnons in quantum information and quantum transport processing.

cond-mat.mes-hall↗

arXiv2024

Chiral-Damping-Enhanced Magnon Transmission

The inevitable Gilbert damping in magnetization dynamics is usually regarded as detrimental to spin transport. Here we apply a general feature of chiral non-Hermitian dynamics to a ferromagnetic-insulator--normal-metal heterostructure to show that the strong momentum dependence and chirality of the eddy-current-induced damping also causes beneficial scattering properties: A potential barrier that reflects magnon wave packets becomes unidirectionally transparent in the presence of a metallic cap layer. Passive magnon gates that turn presumably harmful dissipation into useful functionalities should be useful for future quantum magnonic devices.

cond-mat.mes-hall↗