Axion Mie theory of electron energy loss spectroscopy in topological insulators
Abstract
Electronic topological states of matter exhibit novel types of responses to electromagnetic fields. The response of strong topological insulators, for instance, is characterized by a so-called axion term in the electromagnetic Lagrangian which is ultimately due to the presence of topological surface states. Here we develop the axion Mie theory for the electromagnetic response of spherical particles including arbitrary sources of fields, i.e., charge and current distributions. We derive an axion induced mixing of transverse magnetic and transverse electric modes which are experimentally detectable through small induced rotations of the field vectors. Our results extend upon previous analyses of the problem. Our main focus is on the experimentally relevant problem of electron energy loss spectroscopy in topological insulators, a technique that has so far not yet been used to detect the axion electromagnetic response in these materials.
- Publication:
-
SciPost Physics Core
- Pub Date:
- September 2021
- DOI:
- 10.21468/SciPostPhysCore.4.3.023
- arXiv:
- arXiv:2002.03804
- Bibcode:
- 2021ScPC....4...23S
- Keywords:
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- Physics - Optics;
- Condensed Matter - Mesoscale and Nanoscale Physics;
- High Energy Physics - Theory
- E-Print:
- Submission to SciPost