80 research outputs found
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
Generation of single skyrmions by picosecond magnetic field pulses
We numerically demonstrate an ultrafast method to create
skyrmions in a ferromagnetic sample by applying a
picosecond (effective) magnetic field pulse in the presence of
Dzyaloshinskii-Moriya interaction. For small samples the applied magnetic field
pulse could be either spatially uniform or nonuniform while for large samples a
nonuniform and localized field is more effective. We examine the phase diagram
of pulse width and amplitude for the nucleation. Our finding could ultimately
be used to design future skyrmion-based devices.Comment: 4.5 pages+Supplemental Materia
Theory of the Interfacial Dzyaloshinskii-Moriya Interaction in Rashba Antiferromagnets
In antiferromagnetic (AFM) thin films, broken inversion symmetry or coupling
to adjacent heavy metals can induce Dzyaloshinskii-Moriya (DM) interactions.
Knowledge of the DM parameters is essential for understanding and designing
exotic spin structures, such as hedgehog Skyrmions and chiral N\'eel walls,
which are attractive for use in novel information storage technologies. We
introduce a framework for computing the DM interaction in two-dimensional
Rashba antiferromagnets. Unlike in Rashba ferromagnets, the DM interaction is
not suppressed even at low temperatures. The material parameters control both
the strength and the sign of the interfacial DM interaction. Our results
suggest a route toward controlling the DM interaction in AFM materials by means
of doping and electric fields.Comment: 4.5 pages+references, 4 figure
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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