ABINIT Discussion Forums

Would you notice that "spinors" changes the spgroup to be another one. I don't remember the details anymore, unfortunately. It wasn't anything obvious like changing the spgroup. Instead, I got a segfault in the middle of the calculation for no reason, and this only happened to some system...

You mean indirect band gap? Yes. It has no preference over direct vs indirect gap.

so how about Xred in 2nd option? In the caption of Table I in the referenced paper, the A, B, and O atoms (Ca, W, and O in this case) are given the coordinates (0,1/4,5/8), (0,1/4,1/8), and (x,y,z). Using the alternative origin or coordinates, as mentioned in the text, you get the numbers that are ...

These are the scaling factors for the Cartesian coordinates, which also serve as lattice constants for this system. Instead of writing scalecart 2*5.2429 11.3737 angstrom rprim -0.5 0.5 0.5 0.5 -0.5 0.5 0.5 0.5 -0.5 you could also write rprim -4.95382 4.95382 10.7466 4.95382 -4.95382 10.7466 4.95382...

I can't log in to the website that you posted and am thus unable to comment on the differences in the lattice constants. Perhaps they used a different reference. "2*5.2429" is short for "5.2429 5.2429", meaning that that line is parsed into scalecart 5.2429 5.2429 11.3737 angstro...

It seems to have been just a really difficult structure to relax. With ionmov 7 it converged after about 130 cycles. Using that as input, it also converges with ionmov 2.

Here is an example to get you started. CaWO4 is in space group 88 (tetragonal). If you know rprim and xred, the input can be something like scalecart 2*5.2429 11.3737 angstrom rprim -0.5 0.5 0.5 0.5 -0.5 0.5 0.5 0.5 -0.5 ntypat 3 znucl 20 74 8 natom 12 typat 1 2 3 3 1 2 3 3 3 3 3 3 xred 5.0000000000...

I'm studying a material with 52 atoms in the unit cell. For the pure material I can do structural optimization and calculate other things just fine. However, when I substitute one of the atoms with an impurity atom, structural optimization is unable to converge. That is, the maximal force value (max...

I save the PP with the psp8 extension. I suggest you try it on Linux. I'm not familiar with Windows and am thus unable to help in that regard.

Works for me. Make sure you use at least version 7.10.5. If there are still issues, find older pseudopotentials here http://www.abinit.org/downloads/psp-links/pseudopotentials.

What is the error message? Perhaps you should be using a newer version of Abinit? Just a guess.

The structure of the 'files' file is described here: m. Yes, you should replace 14si.pspnc with your own ones (either relative or full path). Each PP should be on a separate line. The PAW formalism is conceptually different, but from the user's point of view, analogous, to the pseudopotential approx...

I tried using the one that was used for bulk Si in the tutorial exercises You meant the same type, not literaly the same PP, right? In any case, for In and As you can find pseudopotentials at the Abinit website -> Atomic Data/Pseudopotentials -> Norm-conserving pseudopotentials. I am however not su...

mcwang wrote:can PDOS results from each l channel directly sum to the total atom-resolved DOS?

I'm afraid not. You would need to do that manually or write a small post-processing tool.

What's wrong with simply calculating the PDOS and summing over l-channels for each atom?

I was indeed talking about a different thing (the eigen1 array). I see now that you instead referred to the anaddb output.
anaddb should report the correct eigendisplacements, see displ at the end of 72_response/phfrq3.F90.

Hi, it's good to see that someone else has interest in this.

charlesdarnay wrote:the first part for each number is the real part, while the second line is the imaginary part.

If I read eigen1 into a complex array, this removes the first index.

Could somebody please provide me detailed instructions for extracting the electron-phonon matrix elements from the code? For simplicity, let's take nsppol 1. Basically, this is my current understanding: ⋅ The array eigen1 contains the elements of the first order perturbing hamiltonian, as ...

Never mind. I was using the wrong pseudopotential.
Notice for others: when downloading an HGH PP from the Abinit website, the blue and green areas are actually different links. Be careful where you click!

Interestingly, I'm having difficulty understanding how to write input for a simple cubic cell. When I do structural optimization for CsI I get a lattice constant of 6.0 bohr, which, taking into account the slight underestimation of LDA, is sqrt(2) times smaller than the experimental value of 8.629 (...

how I could best test the validity of these "new" setups. Go to m and click on either "Small core datasets" or "Large core datasets". Then pick an element, e.g., Si, and click on "Si data". The reported lattice constant and bulk modulus are from accurate LAPW...

I'm not an expert on graphene but your calculation seems to be correct. The indirect gap obtained from the band structure plot coincides with the one under gap info, so there's no problem with that. I'm not sure where you get the gap value as zero (perhaps the degeneracy at B confuses somehow). The ...

For a converged calculation, they should be the same. Otherwise, it depends on the input file. How much do they differ in your case? Under Gap info, you can see the coordinates of the k-points that Abinit is considering as band extrema: Top of valence bands at : Bottom of conduction at : If these co...

If by exact you mean within the capabilities of the LDA, then yes. If you mean the experimental single-particle band gap, then no. In principle, the difference between the lowest unoccupied and the highest occupied state plus a derivative discontinuity in the exchange-correlation energy would give y...

The array for holding the momentum matrix elements, 'pmat', is declared in optic.F90 as complex(dpc),allocatable :: pmat(:,:,:,:,:,:) Next, it is allocated with ABI_ALLOCATE(pmat,(2,mband,mband,nkpt,3,nsppol)) and then passed to pmat2cart where the dummy variable is complex(dpc),intent(out) :: pmat(...