[Wien] density matrix normalization - expectation spin value

[Robert Laskowski]

Yes, lapw2 calculates also interstitial charge density (fourir.F). You can try to hack this, and add a routine that integrates
the charge density in interstitia, there should be one in mixer source. Then interface it with your modified version of lapwdm.

lapw2 does not calculate the off diagonal part of the spin density matrix, which is non zero if SOC is present.
If you are not interested  in SOC, then easiest would be to use filtvec program that filters vectors, strip it from  all 
states except the one you are interested in and run lapw2 and mixer to get the charge in interstitial.


regards

On Thursday 04 February 2010 20:16:29 Martin Gmitra wrote:
> Hi Robert,
> Is there a way to include this somehow?
> Thanks,
> Martin
> 
> 
> On Thu, Feb 4, 2010 at 9:44 AM, Robert Laskowski <
> rolask at theochem.tuwien.ac.at> wrote:
> 
> > Hi,
> > you are missing interstitial contribution.
> >
> > regards
> >
> > On Thursday 04 February 2010 09:36:53 Martin Gmitra wrote:
> > > Dear Wien2k users,
> > >
> > > We are interested in calculation of expectation value of spin for a state
> > |n,k>,
> > > where n is the band index and k is the wave vector. For this purpose we
> > have
> > > slightly modified lapwdm program. The problem we are encountering is that
> > the
> > > expectation value of z-component of Pauli matrix (sigma_z) is not equal
> > one.
> > > Let us assume for simplicity spin-up state |n,k> and no spin-orbit
> > coupling.
> > > The expectation value for sigma_z we calculate as
> > >
> > > sum_a ( rho_{n,k,a} sigma_z ) not= 1  (it is smaller then 1, typical
> > > range 0.6-0.9)
> > >
> > > where sum_a is the summation over atoms in unit cell.
> > >
> > > 1. Why we do not obtain for the state |n,k> expectation value equal one?
> > > It is rather obvious that in this example <n,k| sigma_z |n,k> =1.
> > >
> > > 2. What is the density matrix normalization in this case?
> > >
> > > rho_{n,k,a} is in this simple example 2x2 matrix having only up-up
> > component,
> > > which is given as Trace in orbital subspaces (sum for L=0,1,2,3) of given
> > state
> > > |n,k>.
> > >
> > > Many thanks in advance,
> > > Martin
> > >
> > > [We are running Wien2k v9.1]
> > > _______________________________________________
> > > Wien mailing list
> > > Wien at zeus.theochem.tuwien.ac.at
> > > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> > >
> > >
> >
> >
> >
> > --
> > Dr Robert Laskowski
> >
> > Vienna University of Technology,
> > Institute of Materials Chemistry,
> > Getreidemarkt 9/165-TC, A-1060 Vienna
> >
> > tel. +43 1 58801 15675
> > Fax  +43 1 58801 15698
> > _______________________________________________
> > Wien mailing list
> > Wien at zeus.theochem.tuwien.ac.at
> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> >
> 



-- 
Dr Robert Laskowski

Vienna University of Technology, 
Institute of Materials Chemistry, 
Getreidemarkt 9/165-TC, A-1060 Vienna

tel. +43 1 58801 15675
Fax  +43 1 58801 15698