How to obtain Kerr angle?

[shench]

Dear Developers,

I have successfully generated the alpha and beta files using YAMBO 5.3.0, and I have a couple of questions regarding the data that I would love your help with:

1. Could you kindly clarify the physical units used in the two output files?
2. Could you also guide me on how to use the data from these files to calculate the Kerr rotation angle?

Thank you so much for your help!

Best regards,
Chenhai

[Davide Sangalli]

Dear Chenhai,
here a tutorial on the magneto-optical kerr effect: https://wiki.yambo-code.eu/wiki/index.p ... err_effect

In extended systems (3D) yambo will generate the files ".eps" and ".off" which contain eps_xx and eps_xy respectively, e.g. the diagonal and off diagonal elements of the dielectric tensor (provided that you properly set the directions in the input file)
Please also check the equations and the "warning footnote" in the tutorial.

In your case, you got ".alpha" and ".beta" likely because you have a system with reduced dimensionality (0D/1D/2D)
These file contain alpha_xx and alpha_xy respectively, e.g. the diagonal and off diagonal elements of the polarizability tensor. The units of the tensor depend on the dimensionality (Volume for 0D, Surface fo 1D, length for 2D), and are in atomic units.
For such case the definition of the Kerr angle needs to be generalized. It will likely depend on what is measured experimentally.

Best,
D.

[shench]

Thank you!