Topological Antiferromagnetic Magnons.


We have studied a model for a non-collinear but coplanar antiferromagnetic spin tex- ture on a two dimensional kagome lattice structure in the presence of Dzyaloshinskii- Moriya Interaction (DMI).

We observed some interesting topological properties in our system i.e. the presence of non-trivial edge state in the wave function.

This non-trivial edge state, which mainly surfaced in the presence of the DMI, showed robustness against the external magnetic   eld and thus can be further studied to    see how important transport properties can be computed.


Background Of Study

The last two decades have witnessed tremendous work in the study of collective excitations of electron’s spins called spin waves.

Spin waves are disturbance of the magnetic ordering that travel through the magnetic material. In the quantum picture, the excitations can be described by magnons.

Magnons are chargeless low- energy collective excitations of localized neighboring spins, with a xed amount of energy and play the vital role of an elemental magnetic carrier in numerous insulating magnets.

Due to their intrinsic bosonic nature, magnons can form a macroscopic coherent state and propagate spin information over several millimeters, much farther than spin-polarized conduction electrons in metals.

With these interesting and fascinating properties, there are possibilities of utilizing magnons as a carrier to propagate information in a unit of Bohr magneton in spin-based devices, these have attracted considerable attention over the last decade.

Antiferromagnetic materials (AFMs) are materials in which electron spin asso- ciated to individual atom at particular lattice point are ordered antiparallel relative to each other such that their net magnetization is equal to zero.

This phenomenon occurs below a reference temperature, known as the Neel temperature (TN ) , above this temperature, the material loses its order and behaves just like a paramagnetic material. Among the properties that make AFMs a promising material for new functionalities include:- absence of stray elds, robustness against magnetic eld perturbation, ultrafast dynamics.

Looking at these properties, in addition to the fascinating properties of magnons mentioned above, it is only natural to be funda- mentally interested in understanding the basis of magnon transport in insulating antiferromagnets.


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