Messages

1

General Questions and Answers / Re: total energy of Green's function calculation

« on: January 26, 2023, 04:28 »

The difference of 15 eV is of the total energy, not per atom. The number of atoms are the same for periodic and Green's function calculations. The reason I want to do this comparison is curiosity. I am learning the Green's function method, and I am wondering on what extent does the Green's function method is equivalent to periodic calculations.
In principle, these two calculations shall be equivalent, so the difference in total energy must result from the interface between leads and the scattering region. So, could you please provide more details on how QuantumATK dealing with the lead/scattering region interface?

Best,
Yun-Peng

2

General Questions and Answers / total energy of Green's function calculation

« on: January 25, 2023, 16:45 »

I understand that the Green's function method does not have a "total energy" equivalent to periodic calculations due to the charge transfer between leads and device. However, if I simulate a crystal using Green's function method, that is, setting the lead and the device to be the same material, there shall be no charge transfer at all; therefore the total energy from Green's function calculations shall be the same with periodic calculations. I use hexagonal BN as an example, however the results show a difference of 15.5 eV. I cannot understand why. Please give suggestions. Thank you very much!
Yun-Peng