60 research outputs found
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 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.
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