Chapter 9
Symmetry Approach to Chiral
Optomagnonics in Antiferromagnetic
Insulators
Igor Proskurin and Robert L. Stamps
Abstract We discuss several aspects of chiral optomagnonics in antiferromagnetic
insulators by considering common symmetries between the electromagnetic field and
spin excitations. This approach allows us to look at optical and magnetic materials
from similar perspectives, and discuss useful analogies between them. We show that
spin waves in collinear antiferromagnets and the electromagnetic field in vacuum are
both invariant under the same eight-dimensional algebra of symmetry transformations. By such analogy, we can extend the concept of optical chirality to antiferromagnetic insulators, and demonstrate that the spin-wave dynamics in these materials
in the presence of a spin current is similar to that of the light inside chiral metamaterials. Photo-excitation of magnonic spin currents is also discussed from the
symmetry point of view. It is demonstrated that a direct magnonic spin photocurrent
can be exited by circularly polarized light, which can be considered as a magnonic
analogue of the photogalvanic effect. We also note that the Zitterbewegung process
should appear and may play a role in photo-excitation processes.
9.1 Introduction
Modern spintronics is now a well-developed area that aims at bringing new functionality to conventional electronics by making use of the spin degrees of freedom
[1], which may help to overcome looming saturation of Moore’s Law [2]. There are
a number of different trends in the development of the spintronics today. Among
different materials, antiferromagnets play an important role, which brings us to the
I. Proskurin (B) · R. L. Stamps
Department of Physics & Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
e-mail: Igor.Proskurin@umanitoba.ca
R. L. Stamps
e-mail: Robert.Stamps@umanitoba.ca
I. Proskurin
Institute of Natural Sciences and Mathematics, Ural Federal University,
Ekaterinburg 620002, Russia
© Springer Nature Switzerland AG 2021
E. Kamenetskii (ed.), Chirality, Magnetism and Magnetoelectricity,
Topics in Applied Physics 138,
https://doi.org/10.1007/978-3-030-62844-4_9
207
Symmetry Approach to Chiral
Optomagnonics in Antiferromagnetic
Insulators
Igor Proskurin and Robert L. Stamps
Abstract We discuss several aspects of chiral optomagnonics in antiferromagnetic
insulators by considering common symmetries between the electromagnetic field and
spin excitations. This approach allows us to look at optical and magnetic materials
from similar perspectives, and discuss useful analogies between them. We show that
spin waves in collinear antiferromagnets and the electromagnetic field in vacuum are
both invariant under the same eight-dimensional algebra of symmetry transformations. By such analogy, we can extend the concept of optical chirality to antiferromagnetic insulators, and demonstrate that the spin-wave dynamics in these materials
in the presence of a spin current is similar to that of the light inside chiral metamaterials. Photo-excitation of magnonic spin currents is also discussed from the
symmetry point of view. It is demonstrated that a direct magnonic spin photocurrent
can be exited by circularly polarized light, which can be considered as a magnonic
analogue of the photogalvanic effect. We also note that the Zitterbewegung process
should appear and may play a role in photo-excitation processes.
9.1 Introduction
Modern spintronics is now a well-developed area that aims at bringing new functionality to conventional electronics by making use of the spin degrees of freedom
[1], which may help to overcome looming saturation of Moore’s Law [2]. There are
a number of different trends in the development of the spintronics today. Among
different materials, antiferromagnets play an important role, which brings us to the
I. Proskurin (B) · R. L. Stamps
Department of Physics & Astronomy, University of Manitoba, Winnipeg R3T 2N2, Canada
e-mail: Igor.Proskurin@umanitoba.ca
R. L. Stamps
e-mail: Robert.Stamps@umanitoba.ca
I. Proskurin
Institute of Natural Sciences and Mathematics, Ural Federal University,
Ekaterinburg 620002, Russia
© Springer Nature Switzerland AG 2021
E. Kamenetskii (ed.), Chirality, Magnetism and Magnetoelectricity,
Topics in Applied Physics 138,
https://doi.org/10.1007/978-3-030-62844-4_9
207