QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: xhsh on September 15, 2010, 16:04

Title: Is the convergence considered for the denxity matrix or the charge density?
Post by: xhsh on September 15, 2010, 16:04

In siesta, the convergence is considered for the density matrix. In ATK, is it considered for density matrix or the charge density at each point in the real space? Thanks a lot.

Title: Re: Is the convergence considered for the denxity matrix or the charge density?
Post by: Nordland on September 15, 2010, 16:58

The hamiltonian. However the density matrix is always converged to same degree or better than the Hamiltonian when the Hamiltonian is converged.

Title: Re: Is the convergence considered for the denxity matrix or the charge density?
Post by: xhsh on September 16, 2010, 02:31

Thanks!

I want to further ask about the density matrix. For a two-probe system with different electrodes, how is the total charge calculated? By the formula Q=Tr(DS) (where D is the density matrix and S is the basis overlap matrix), just like in Siesta? Or just by integrating the electron density in the real space?

Title: Re: Is the convergence considered for the denxity matrix or the charge density?
Post by: Nordland on September 16, 2010, 08:39

Ahh, it is the older version?

Yes, the charge is calculated as the trace of the density matrix and the overlap.