[Pw_forum] A Question about ILDOS on different planes

[Gabriele Sclauzero]

Il giorno 05/ott/2011, alle ore 18.28, pari shok ha scritto:

> Dear Gabriel,
> Thank you very much for your answer.
> The original problem that I need to solve is getting the local density of states on different planes of the structure. As you know, QE calculates 3D-DOS of the structure and I need to convert it to quasi-2D-DOS, somehow.

What is "quasi-2D-DOS"? Could you please make an effort to define better the quantity that you want to plot?

> This is what is done by "Takahiro Yamasaki et al.", in "Geometric and electronic structures of SiO2/Si(001)… interfaces"; they divided the unit cell into 1.0 a.u. (50.529 Å) thick slices parallel to the interface, and specify each slice as a local region, and then define a local density of states for each region. 
> I need to do the same thing for my structure, and I was wondering if (and how)I can get it with QE.

Again, so how do they define that? Sorry, I'm not going to read that paper to understand what you need...

> I know ILDOS is the integration in a range of energy.
> What I wanted to do was finding ILDOS on planes (I don't know how) for a very small fraction of energy each time to get them all in a wide range of energies to have a rough estimate of LDOS on the parallel planes.
> My structure is hexagonal with vacuum in z direction. I got all the x0(i)=0 (I thought I didn't need to change the origin given by x0(i), while I change e3) and iflag=2.

Please read CAREFULLY the INPUT_PP documentation and example01, as I suggested in my previous email. Since you want a 2D plot you need to use iflag=2 (as you do), so the e3 vector will NOT be used. Instead, you'll definitely need to change x0 if you want to plot the ILDOS on different planes.
Suppose your planes are normal to the z axis. Then e1 and e2 need to be chosen according to the size and shape of the basal plane of your unit cell (you could take the first and second unit vectors of the hexagonal cell, see INPUT_PW), while z will run from (0,0,0) to (0,0,celldm(3)), for instance.

> I need to get 2D-DOS for further calculation, thus I don't need to visualize, just the data.
> A couple of months ago, I thought that I might have got LDOS on planes by summing the partial projected DOS of all atoms at the interface (which I guess it was silly).

PDOS != LDOS

> If you (or anybody) could give me hints, I would really appreciate.

I did, now I hope you make your best to understand and go on by yourself.


GS

> Yours
> P Shock
> PhD candidate UMD _______________________________________________
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§ Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne







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