[lammps-users] electron-phonon and thermal coupling of TTM and ATC


first of all I would like to thank the LAMPPS-community for their fast response and want to apologize that my
question was not asked as clear as possible. Even though, the answers helped me a lot. Only one question
I want to simulate a process where metal gets irradiated by phonons (a laser as source) until a part is melted and
maybe even vapourized. The vapourization happens at least in reality. Therefore I want to model the following:
A basic MD part which simulates the part of the metal where melting and vapourization takes place. The atom force
field should be the MEAM. I will also need the TTM for modeling the photon absorption by the conduction band electrons
and the fast heat conduction within the electrons. Due to the fact that the MD cell would vapourize very fast, I want to combine the MD cell to an FD cell which represents the bulk of the metal, i.e. the solid part. Therefore I need a thermal connection between the MD and FD part. This I would like to model with ATC.
For this simulation, I got the following question:
As far as I’m concerned, the TTM can only model a phonon-electron interaction for atoms close to equillibrium with the
part which is called electron-ion interaction in the LAMPPS manual. My model will simulate a highly non-equilibrium process.
So, will it be possible to connect my TTM part to the ATC part in two ways:
Firstly, that I can have a phonon-electron interaction from the ATC part to the electron ‘gas’ simulated by the TTM.
Secondly, that there’s an thermal connection between the atom lattice simulated by the MEAM and the electron ‘gas’ from the TTM to the ATC in a way that the heat from the MD part goes to the FD part. I.e. the bulk metal cools down the
temperature of the melted part.

In advance I thank you very much for your answers. Best Regards,

I suggest you read the doc pages and cited papers
(and look at the code if necessary)
for fix ttm and for the USER-ATC package. Your questions are
detailed enough, I think you need to study what the features say
they will do and see if it satisfies your model.


Did you see reference Phys. Rev. B68,064114 (2203).
It looks like the authors do something similar to what you describe.
They have “direct” energy transfer between the electronic and atomic systems instead of the transfer through Langevin thermostat,
how it’s realized in “fix ttm”. But the last realization should be more accurate.
German Samolyuk