HartreeDifferencePotential - spin projection

[hagelberg]

I'd like to compute spin projections of the Hartree Difference Potential, specifically projections on spin-up/spin-down populations, and the difference between both. Could you suggest a script that would achieve this? I have access to QuantumATK S-2021.06. Thanks!

[filipr]

I don't think this is currently possible for a user to do.

The reason is that both during the SCF loop and when using HartreePotential to calculate the Hartree potential only the full electron density is used. This is both to ensure that no unnecessary computations are done (solving the Poisson equation is not always a cheap operation) and ensure that the correct boundary conditions are satisfied. In fact the Hartree potential is by definition a scalar quantity - it is an electrostatic potential.

You could in principle calculate the electrostatic potential from the spin-up and spin-down part of the electron density, but that would require you to extract those two densities and solve the Poisson equation separately for each one. I don't think this is possible for a user to do.