Tunable topological magnon-polaron states and anomalous Hall phenomena in two-dimensional ferromagnetic insulators

We study magnon-polaron hybrid states, mediated by Dzyaloshinskii-Moriya and magnetoelastic interactions, in a two-dimensional ferromagnetic insulator. The magnetic system consists of both in-plane and flexural acoustic and optical phonon bands, as well as acoustic and optical magnon bands. Through manipulation of the ground-state magnetization direction using a magnetic field, we demonstrate the tunability of Chern numbers and (spin) Berry curvatures of magnon-polaron hybrid bands. This adjustment subsequently modifies two anomalous Hall responses of the system, namely, thermal Hall and spin Nernset signals. Notably, we find that by changing the magnetic field direction in particular directions, it is possible to completely suppress the thermal Hall signal while maintaining a finite spin Nernst signal. Our finding reveals the intricate interplay between topological and quantum geometrical phenomena and magnetic ordering, offering compelling avenues for on-demand control over emergent quantum states in condensed matter systems.Comment: 13 pages, 7 figure

Staggered Dynamics in Antiferromagnets by Collective Coordinates

Antiferromagnets can be used to store and manipulate spin information, but the coupled dynamics of the staggered field and the magnetization are very complex. We present a theory which is conceptually much simpler and which uses collective coordinates to describe staggered field dynamics in antiferromagnetic textures. The theory includes effects from dissipation, external magnetic fields, as well as reactive and dissipative current-induced torques. We conclude that, at low frequencies and amplitudes, currents induce collective motion by means of dissipative rather than reactive torques. The dynamics of a one-dimensional domain wall, pinned at 90$^{\circ}$ at its ends, are described as a driven harmonic oscillator with a natural frequency inversely proportional to the length of the texture.Comment: 4 pages, 2 figure

The Medicine Line: A Border Dividing Tribal Sovereignty, Economies and Families

Contains fulltext : 194983.pdf (publisher's version ) (Open Access)7 p

Ground-state properties of gapped graphene using the random phase approximation

We study the effect of band gap on the ground-state properties of Dirac electrons in a doped graphene within the random phase approximation at zero temperature. Band gap dependence of the exchange, correlation and ground-state energies and the compressibility are calculated. We additionally show that the conductance in the gapped graphene is smaller than gapless one. We also calculate the band gap dependence of charge compressibility and it decreases with increasing the band gap values.Comment: 11 pages, Final version. To appear in Phys. Rev.