The microscopic Einstein-de Haas effect
File(s)
Accepted version
Author(s)
Wells, Tomos
Horsfield, Andrew
Foulkes, William Matthew Colwyn
Dudarev, Sergei
Type
Journal Article
Abstract
The Einstein-de Haas (EdH) effect, where the spin angular momentum of electrons is transferred to the mechanical angular momentum of atoms, was established experimentally in 1915. While a semiclassical explanation of the effect exists, modern electronic structure methods have not yet been applied to model the phenomenon. In this paper, we investigate its microscopic origins by means of a noncollinear tight-binding model of an O2 dimer, which includes the effects of spin-orbit coupling, coupling to an external magnetic field, and vector Stoner exchange. By varying an external magnetic field in the presence of spin-orbit coupling, a torque can be generated on the dimer, validating the presence of the EdH effect. The avoided energy level crossings and the rate of change of magnetic field determine the evolution of the spin. We also find that the torque exerted on the nuclei by the electrons in a time-varying B field is not only due to the EdH effect. The other contributions arise from field-induced changes in the electronic orbital angular momentum and from the direct action of the Faraday electric field associated with the time-varying magnetic field.
Date Issued
2019-06-14
Date Acceptance
2019-05-21
Citation
Journal of Chemical Physics, 2019, 150 (22)
ISSN
0021-9606
Publisher
AIP Publishing
Journal / Book Title
Journal of Chemical Physics
Volume
150
Issue
22
Copyright Statement
© 2019 Author(s). Published under license by AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in J. Chem. Phys. 150, 224109 (2019) and may be found at https://dx.doi.org/10.1063/1.5092223
Sponsor
Engineering and Physical Sciences Research Council
United Kingdom Atomic Energy Authority
Identifier
https://aip.scitation.org/doi/10.1063/1.5092223
Grant Number
EP/L015579/1
300207034
Subjects
Chemical Physics
02 Physical Sciences
03 Chemical Sciences
09 Engineering
Publication Status
Published
Article Number
224109