[Wien] [SPAM?] same k vector, different eigenvectors

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Dear all,

I am runing a one-step calculation to get the eigenvector of ferromagnetic BCC-Fe at k=(1,1,1) from a self-consistent charge density. The command used is ' runsp_lapw -so -p -s lapw1 -e lapwso'.




First i get the self-consistent charge density by using 'runsp_lapw -ec 0.0001 -cc 0.0001 -p -i 100 -so'. Then i copy the scf results to two directories and change the klist respectively. In one directory, i use only two k-points (0,0,0) and (1,1,1) in klist as:




         1         0         0         0         1  1.0 -7.0  1.5         1 k, div: (  1  1  1)
         2        10        10        10        10  1.0
END,




and in another directory i use101 k-points including (1,1,1) as:




...

        99        10         9         9        10  8.0
       100        10         8        10        10  4.0
       101        10        10        10        10  1.0
END.




As a consequence, I get two results about eigenvectors at k=(1,1,1) in these two directory. I find that the two results are not identical. In the 2-kpts case, the lowest eigenvalue and eigenvector in vectorsoup file is:




           1  -5.83325860040616
 -0.149115553408975       5.906541789778055E-002 -0.149115710346805
  5.906548006164127E-002 -0.149115710346904       5.906548006168073E-002
 -0.149115710346889       5.906548006167468E-002 -0.149115710346984
  5.906548006171229E-002 -0.149115553409014       5.906541789779599E-002
...,





while in the 101-kpts case, it is:




           1  -5.83325860040616
 -2.301711645066824E-004  0.160387402501481      -2.301714067522111E-004
  0.160387571302459      -2.301714067523196E-004  0.160387571302571
 -2.301714067523697E-004  0.160387571302556      -2.301714067524974E-004
  0.160387571302664      -2.301711645069168E-004  0.160387402501536
....




In my understanding, the hamiltonian is only k-dependent but not k-mesh denpendent. So i should get the same hamiltonian in the two directories at same k-point, so as the eigenvector. Did i do something wrong? Or what misunderstanding do i have? If not, why are not the eigenvectors exactly the same?




I am wondering if anyone has encountered a similar issue or has any insights on why this may be happening. Any suggestions or advise would be greatly appreciated.

Thank you in advance. 

Best regards, Yingying Cao
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