[Wien] Error Calculating Bi Surface Bands

Matthew Xia xiay at princeton.edu
Tue Dec 11 05:06:57 CET 2007


Hello,
  Thank you Professor Blaha and Faccio for your messages. About the crystal
structure, I am using a supercell comprised of 10 unit cells in the z
direction, with 6 atoms per unit cell, so there are 60 atoms. In
otherewords, it's 60 layers instead of 10. The first few entries generated
by supercell is given by:

*H   LATTICE,NONEQUIV. ATOMS 10
MODE OF CALC=RELA unit=bohr
  8.569908  8.569908227.252250 90.000000 90.000000120.000000
ATOM   1: X=0.00000000 Y=0.00000000 Z=0.07525172
          MULT= 6          ISPLIT=15
ATOM   1: X=0.00000000 Y=0.00000000 Z=0.02298812
ATOM   1: X=0.66666667 Y=0.33333333 Z=0.00975849
ATOM   1: X=0.66666667 Y=0.33333333 Z=0.05573474
ATOM   1: X=0.33333333 Y=0.66666667 Z=0.04250511
ATOM   1: X=0.33333333 Y=0.66666667 Z=0.08848135
Bi         NPT=  781  R0=0.00000500 RMT=    2.0000   Z: 83.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000

*After running symmetry, I adopted the struct generated by the file, given
by:
*H   LATTICE,NONEQUIV.ATOMS: 60 156
P3m1

RELA
  8.569908  8.569908227.252250 90.000000 90.000000120.000000

ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT= 4
Bi1        NPT=  781  R0=0.00000500 RMT=    2.5000   Z: 83.0

LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.00000000 Y=0.00000000 Z=0.94773640
          MULT= 1          ISPLIT= 4
Bi2        NPT=  781  R0=0.00000500 RMT=    2.5000   Z: 83.0

LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
*So the number of inequivalent atoms has been increased by symmetry. Should
I not accept the struct file generated by it? Also, as a side question along
the same vein, for the surface bands is 1x1 unit cell in the x-y direction
sufficient? Ans is the 5x5x1 k-mesh sufficient for that purpose? I used
2x2x10 before but I am trying to minimize the number of unit cells used to
save calculation time.

The calculation doesn't seem to be converging,
DIS  :  CHARGE DISTANCE       ( 0.1641572 for atom   37 spin 1)
0.1545264
DIS  :  CHARGE DISTANCE       ( 0.1913422 for atom    3 spin 1)
0.1529912
...
DIS  :  CHARGE DISTANCE       ( 1.1335284 for atom   51 spin 1)
0.5305745
DIS  :  CHARGE DISTANCE       ( 1.1275002 for atom   18 spin 1)
0.6506100
...
DIS  :  CHARGE DISTANCE       ( 0.3828902 for atom   49 spin 1)
0.1680688
DIS  :  CHARGE DISTANCE       ( 0.4418754 for atom   46 spin 1)
0.2222958
DIS  :  CHARGE DISTANCE       ( 0.4079805 for atom   47 spin 1)
0.2201738

I will try to run a calculation without -scf. I did not do so before because
each calculation takes at least 2 weeks, and the system is unphysical
without spin-orbit coupling. Could you please explain why the calculation is
not converging?

Thank you.
Sincerely yours,
Matthew Xia

On Dec 10, 2007 2:03 AM, Peter Blaha <pblaha at theochem.tuwien.ac.at> wrote:

> First of all, please check your convergence (grep :DIS case.scf)
> Is it converging or diverging ?
>
> Second: I'm not sure if it matters, but remove the line
>  >  0   -4.97      0.005       atom number,e-lo,de (case.in1), repeat NX
> from your inso file (You specified correctly "0" RLOs, so this line
> should not be there).
>
> Did you run without -so before ? Usually this should be the first step.
>
> Your error ocured for atom 44 ? Why do you have all 60 atoms
> non-equivalent ? I'd expect some symmetry ?
> Ad I do not understand either why a 10 layer cell has 60 atoms ?
>
>
> Matthew Xia schrieb:
> > Hello Wien Users,
> >  Many thanks first to the forum for providing guidance to the wien
> > package. I am interested in calculating the surface state of Bi, using a
> > 1x1x10 supercell (10 bilayers) with a 5x5x1 k-mesh.  After initializing
> > the calculation and accepting the geometry offered by nn, I ran the scf
> > with spin orbit coupling. The calculation ran for 21 iterations, until
> > at the end of the 22nd the calculation stopped:
> > / cycle 22 (Fri Dec  7 14:45:49 EST 2007) (19/19 to go)
> >
> >  >   lapw0 (14:45:49) 228.126u 1.693s 3:56.95 96.9% 0+0k 0+0io 24pf+0w
> >  >   lapw1  -c   (14:49:47) 9935.601u 146.192s 7:40:52.37 36.4% 0+0k
> > 0+0io 640167pf+0w
> >  >   lapwso  -c (22:30:44) 2084.313u 31.731s 1:26:14.72 40.8% 0+0k 0+0io
> > 117209pf+0w
> >  >   lapw2 -c -so   (23:57:03) 1310.015u 166.919s 31:28.94 78.1% 0+0k
> > 0+0io 4578pf+0w
> >
> >  >   stop error
> > /
> > Tha lapw2.error reads:/ 'l2main' - QTL-B.GT.15., Ghostbands, check scf
> > files/
> >
> > and the end of scf2 file reads:    /QTL-B VALUE .EQ. **********   in
> > Band of energy   -4.74977   ATOM=   44   L=  0
> >    Check for ghostbands or EIGENVALUES BELOW XX messages
> >    Adjust your Energy-parameters or use -in1new switch, check RMTs  !!!
> > :WARN : QTL-B value eq.*******  in Band of energy  -4.74977   ATOM=
> > 44   L=  0
> > :WARN : You should change the E-parameter in case.in1 or use -in1new
> switch
> >
> > /I  have used the same RMT values and energy-parameters before to do
> > bulk calculations with the Bi unit cell, and that calculation has ran
> > well without any problems. My in1 file reads:
> > /WFFIL        (WFPRI, SUPWF)
> >   7.00       10    4 (R-MT*K-MAX; MAX L IN WF, V-NMT
> >   0.30    5  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> > APW/LAPW)
> >  2   -1.54      0.010 CONT...
> > 0.000 CONT 1
> > K-VECTORS FROM UNIT:4   -9.0       3.0  519   emin/emax/nband #red
> > /And my inso file reads:
> > /WFFIL
> >  4  1  0                      llmax,ipr,kpot
> >  -10.0000   1.50000           emin,emax (output energy window)
> >    1.  1.  1.                 direction of magnetization (lattice
> vectors)
> >  0                           number of atoms for which RLO is added
> >  0   -4.97      0.005       atom number,e-lo,de (case.in1), repeat NX
> times
> >  0 0 0 0 0                    number of atoms for which SO is switch
> > off; atoms
> >
> > /The SCF file reads, for the last iteration as:
> >    ---------
> > /:ITE001:  1. ITERATION
> >
> > :NATO :   60 INDEPENDEND AND   60 TOTAL ATOMS IN UNITCELL
> >               LATTICE                      = H
> > :POT  : POTENTIAL OPTION   13
> > :LAT  : LATTICE CONSTANTS=  8.56991  8.56991227.25225
> > :VOL  : UNIT CELL VOLUME =   14454.10292
> >        MODE OF CALCULATION IS       = RELA
> >        NON-SPINPOLARIZED CALCULATION
> > :IFFT  : FFT-parameters:   36   36  900 Factor: 1.00
> >        ATOMNUMBER=  1 Bi1        VCOUL-ZERO =  0.21765E+00
> > :EFG001:                        EFG         =    -0.00400   *10**21  V /
> > m**2
> >
> > OVERALL ENERGY PARAMETER IS    0.3000
> >           OVERALL BASIS SET ON ATOM IS LAPW
> >           E( 2)=   -1.2200   E(BOTTOM)=   -1.400   E(TOP)=   -1.040
> >              APW+lo
> >           E( 2)=    0.3000
> >              LOCAL ORBITAL
> >           E( 0)=   -0.7300   E(BOTTOM)=   -1.090   E(TOP)= -200.000
> >              APW+lo
> >           E( 0)=    0.3000
> >              LOCAL ORBITAL
> >           E( 1)=    0.3000
> >              APW+lo
> >
> >        K=   0.00000   0.00000   0.00000            1
> > :RKM  : MATRIX SIZE 6227LOs: 900  RKM= 6.98  WEIGHT= 1.00  PGR:
> >        EIGENVALUES ARE:
> >         -1.3853569   -1.3853569   -1.3817454   -1.3817454   -1.3808292
> >         - 1.3808292   -1.3783348   -1.3783348   -1.3762158   -1.3762158
> >         -1.3741646   -1.3741646   -1.3729990   -1.3707902   ....
> >
> > /Could someone please suggest where the problem might be? Any guidance
> > will be much appreciated.
> >
> > Thank you.
> > MX
> >
> >
> > ------------------------------------------------------------------------
> >
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