Running MLFF MD under external electric field

[inhwankim@utexas.edu]

Hi,

I want to calculate how the vibrational properties of bulk perovskite oxides change under an electric field. To do that, I run MLFF MD (ML_MODE = run) with the INCAR EFIELD tag on. My question is, do I always have to create a vacuum in the direction of the external electric field? What happens if I just apply an electric field without a vacuum? I'm worried if I insert a vacuum layer, the surface effect will dominate and get rid of the electric field effect.

Best,
Inhwan

[manuel_engel1]

Hi Inhwan,

Thanks for reaching out. External electric fields do not make sense in a 3D bulk system. The homogeneous electric field would not create any net effect in a periodic system. That is why the use of EFIELD should be restricted to slabs and molecules. The surface effects are an important part of the physics in this case.

I hope that I was able to answer your question.

[inhwankim@utexas.edu]

Totally!

Thank you for your response.

Inhwan