I've read papers about the Rashba effect, Dresselhaus effect, and Dzyalonshinskii-Moriya Interaction but don't understand fundamentally why breaking spatial symmetry is a pre-requisite to see these effective magnetic fields.
Dear Ryan,
I think that you are thinking in their lack of inversion symmetry, due to have a vector product in their definition.
The breaking of spontaneous symmetry is due to have a change of a order parameter which is no sense in this context. And the breaking of symmetry alone is also without meaning if nothing more is said.
I hope that this can help.
Thanks for the response Daniel!
I did in fact mean inversion asymmetry. I know that the Rashba Hamiltonian (for instance) is inversion asymmetric, but I'm trying to better understand the nature of the interactions.
Can the Rashba field be discussed from the point of view of band theory? Is it the band mismatch between the neighboring materials that causes the Rashba field?
Of course it can be used with bands. In fact it is mainly used with spin-orbit interaction on the bands.
The interfaces between materials is a good place to apply it because you have two dimensional system.
Dear Ryan,
one can indeed show that if both time-reversal (T) symmetry and spatial inversion (P) symmetry are preserved, then each energy band in a crystal is necessarily two-fold degenerate. In other words, a spin splitting of the bands is only possible if either T or P symmetry is broken. This is discussed, for example, in Sec. 16.4 of the textbook [M.S. Dresselhaus, G. Dresselhaus, A. Jorio, Group Theory: Application to the Physics of Condensed Matter, Springer, 2008], or in Appendix A.2 of the attached article.
With best regards
Giulio
Article Functional renormalization and mean-field approach to multib...
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Electromagnetism