Yambo Community Forum

Dear all

I would be very grateful if you could let me know of any possibility of computing chiroptical properties of solids (mainly for plasmons on metal surfaces) with YAMBO, which does not seem so common in periodic systems

regards

Manuel Perez Jigato
Luxembourg Institute of Science and Technology

PS natural optical rotation/circular dichroism etc (linear-reciprocal as compared to Faraday/Kerr effect or second-harmonic generation)

Dear Manuel,
if I understand what you mean, you should be able to compute the chiroptical properties using yambo kerr.
Just compile it (make yambo_kerr) and have a look to the tutorial you can find on he yambo website:
http://www.yambo-code.org/tutorials/KER ... /index.php

With yambo_kerr you have access to all chiroptical properties which can be described via the dielectric tensor.

Best,
D.

Dear Davide

thanks for your reply

I have been looking at the link that you sent, and that seems to be consistent with the
literature I have looked at (magneto-optics)

I seem to have a problem with understanding the following: the bottom equation at the section "few equations"
in your tutorial on Fe Kerr MO seems to be consistent with the fundamental electrodynamics (equation 63 in "Magneto-optical effects in transition metal
systems", H Ebert, Rep Prog Phys 59 (1996) 1665-1735)

n = sqrt(epsilon)

where n is the complex refractive index and epsilon is the dielectric tensor

In fact, for natural circular dichroism and optical rotation, what you look at usually is the difference for both right-circularly polarised and
left circularly polarised light of either the real or the imaginary part of n, and, n has one extra term:

n = sqrt(epsilon*nu) +- alpha for both RCP and LCP

alpha is what I cannot find anywhere in the magneto-optics theory (nu is the magnetic permeability -macroscopic- which for non-magnets is 1, we can forget it)

regards

Manuel
PS alpha originates from the constitutive equations, like D = epsilon E + i alpha, B = nu H - i alpha (i is the square root of -1)

Dear Davide

the references I have been looking at are:

- IV Lindell, AH Sihvola, SA Tretyakov, "Electromagnetic waves in chiral and bi-isotropic media", Artech House, 1994

- Jan Kunes, "Magnetism and magneto-optics in DFT", Physica Scripta, Vol T109 (2004) 116-120

- H Ebert, "Magneto-optical effects in transition metal systems", Rep Prog Phys 59 (1996) 1665

- your PRB 2012 paper

regards

Manuel

Dear Davide

I forgot a couple of things in the consitutive equations (PS in two messages back), ie the cross-fields:

D = epsilon E + i alpha H

B = nu H - i alpha E

regards

Manuel

Dear Manuel,
yambo_kerr computes only epsilon, not alpha.

Best,
D.

Davide Sangalli wrote: ↑Thu Apr 27, 2017 10:03 am Dear Manuel,
yambo_kerr computes only epsilon, not alpha.

Best,
D.

But the dielectric function is ill-defined in 2D, so I want to know is the off-diagonal epsilon that yambo_kerr computes reliable?

Best,
Thank you

Yambo computes the dielectric function in 3D systems (epsilon) and the polarizability (alpha) for lower dimensional systems.
But in any case the quantity which relates the induced polarization to the external electric field.

In the post above Manuel was asking about the quantity relating the polarization to the external magnetic field.
Let me call it "beta". Indeed in the last release of the yambo code it is also possible to compute beta.
But this latter is an experimental feature, only available for moleculer and still under heavy development.
Some references.
https://arxiv.org/abs/2202.12702
https://arxiv.org/abs/2202.02079

Best,
D.

P.S.: please notice that now yambo does everything, no need to compile yambo_kerr anymore