The phononic Klein paradox using magneto-elastic coupling

Abstract

In this Thesis we will investigate how phonons and magnons interact with each other. Using the Klein paradox, where matter-antimatter interactions can cause interesting phenomena in scattering theory. In this thesis we will work out the phononic Klein effect, where phonons will couple with antimagnons with negative energy states. This interaction, facilitated by magneto-elastic coupling from magneto-elastic theory, will cause the same phenomenon as the bosonic Klein effect published a few years ago. An increase of, in our case, phonons in the system, due to the reflection coefficient, R > 1. By working out the dispersion relation for the coupled magnons and phonons, we can see how antimagnons can interact with phonons, giving us the Klein effect. We will end this thesis with an expression for the reflection coefficient, by using scattering theory