[Pw_forum] Strange band structure diagram

[Lun Yue]

Dear pwscf users,

I did some calculations about bulk TiO2 rutile and got a really strange band structure diagram:
http://img840.imageshack.us/i/rutilebands.png/

I checked the input files but could not find the problem, please help me in figuring out it.


Best regards,
Lun Yue

My input files:

======= rutile.scf.in ===============

 &control
    calculation = 'scf',
    prefix = 'rutile_scf',
    verbosity = 'default',
/
 &system
    ibrav = 6, 
    celldm(1) = 8.680890966, 
    celldm(3) = 0.64394729330137, 
    nat =  6, 
    ntyp = 2,
    ecutwfc = 40,
    ecutrho = 400,
    occupations = 'fixed',
    nbnd = 40,
 /
 &electrons
    conv_thr = 1.0e-09,
    electron_maxstep = 100,
    mixing_beta = 0.3,
    conv_thr = 1.0e-08,
    mixing_mode = 'plain',  
 /

ATOMIC_SPECIES
 O 15.999  O.pbe-van_ak.UPF
 Ti 47.867 Ti.pbe-sp-van_ak.UPF
ATOMIC_POSITIONS (angstrom)
Ti  0.00000000  0.00000000  0.00000000
Ti  2.29686500  2.29686500  1.47906000
O   1.40246577  1.40246577  0.00000000
O  -1.40246577 -1.40246577  0.00000000
O   3.69933077  0.89439923  1.47906000
O   0.89439923  3.69933077  1.47906000
K_POINTS (automatic)
  6 6 6 0 0 0



========= rutile.bands.in =============

 &control
    calculation = 'bands',
    prefix = 'rutile_scf',
    verbosity = 'default',
/
 &system
    ibrav = 6, 
    celldm(1) = 8.680890966, 
    celldm(3) = 0.64394729330137, 
    nat =  6, 
    ntyp = 2,
    ecutwfc = 40,
    ecutrho = 400,
    occupations = 'fixed',
    nbnd = 40,
 /
 &electrons
    conv_thr = 1.0e-09,
    electron_maxstep = 100,
    mixing_beta = 0.3,
    conv_thr = 1.0e-08,
    mixing_mode = 'plain',  
 /

ATOMIC_SPECIES
 O 15.999  O.pbe-van_ak.UPF
 Ti 47.867 Ti.pbe-sp-van_ak.UPF
ATOMIC_POSITIONS (angstrom)
Ti  0.00000000  0.00000000  0.00000000
Ti  2.29686500  2.29686500  1.47906000
O   1.40246577  1.40246577  0.00000000
O  -1.40246577 -1.40246577  0.00000000
O   3.69933077  0.89439923  1.47906000
O   0.89439923  3.69933077  1.47906000
K_POINTS crystal
60
        0.5000000000    0.0000000000    0.5000000000    1.0
        0.4750000000    0.0000000000    0.4750000000    1.0
        0.4500000000    0.0000000000    0.4500000000    1.0
        0.4250000000    0.0000000000    0.4250000000    1.0
        0.4000000000    0.0000000000    0.4000000000    1.0
        0.3750000000    0.0000000000    0.3750000000    1.0
        0.3500000000    0.0000000000    0.3500000000    1.0
        0.3250000000    0.0000000000    0.3250000000    1.0
        0.3000000000    0.0000000000    0.3000000000    1.0
        0.2750000000    0.0000000000    0.2750000000    1.0
        0.2500000000    0.0000000000    0.2500000000    1.0
        0.2250000000    0.0000000000    0.2250000000    1.0
        0.2000000000    0.0000000000    0.2000000000    1.0
        0.1750000000    0.0000000000    0.1750000000    1.0
        0.1500000000    0.0000000000    0.1500000000    1.0
        0.1250000000    0.0000000000    0.1250000000    1.0
        0.1000000000    0.0000000000    0.1000000000    1.0
        0.0750000000    0.0000000000    0.0750000000    1.0
        0.0500000000    0.0000000000    0.0500000000    1.0
        0.0250000000    0.0000000000    0.0250000000    1.0
        0.0000000000    0.0000000000    0.0000000000    1.0
        0.0000000000    0.0454545455    0.0000000000    1.0
        0.0000000000    0.0909090909    0.0000000000    1.0
        0.0000000000    0.1363636364    0.0000000000    1.0
        0.0000000000    0.1818181818    0.0000000000    1.0
        0.0000000000    0.2272727273    0.0000000000    1.0
        0.0000000000    0.2727272727    0.0000000000    1.0
        0.0000000000    0.3181818182    0.0000000000    1.0
        0.0000000000    0.3636363636    0.0000000000    1.0
        0.0000000000    0.4090909091    0.0000000000    1.0
        0.0000000000    0.4545454545    0.0000000000    1.0
        0.0000000000    0.5000000000    0.0000000000    1.0
        0.0454545455    0.5000000000    0.0000000000    1.0
        0.0909090909    0.5000000000    0.0000000000    1.0
        0.1363636364    0.5000000000    0.0000000000    1.0
        0.1818181818    0.5000000000    0.0000000000    1.0
        0.2272727273    0.5000000000    0.0000000000    1.0
        0.2727272727    0.5000000000    0.0000000000    1.0
        0.3181818182    0.5000000000    0.0000000000    1.0
        0.3636363636    0.5000000000    0.0000000000    1.0
        0.4090909091    0.5000000000    0.0000000000    1.0
        0.4545454545    0.5000000000    0.0000000000    1.0
        0.5000000000    0.5000000000    0.0000000000    1.0
        0.5000000000    0.5000000000    0.0294117647    1.0
        0.5000000000    0.5000000000    0.0588235294    1.0
        0.5000000000    0.5000000000    0.0882352941    1.0
        0.5000000000    0.5000000000    0.1176470588    1.0
        0.5000000000    0.5000000000    0.1470588235    1.0
        0.5000000000    0.5000000000    0.1764705882    1.0
        0.5000000000    0.5000000000    0.2058823529    1.0
        0.5000000000    0.5000000000    0.2352941176    1.0
        0.5000000000    0.5000000000    0.2647058824    1.0
        0.5000000000    0.5000000000    0.2941176471    1.0
        0.5000000000    0.5000000000    0.3235294118    1.0
        0.5000000000    0.5000000000    0.3529411765    1.0
        0.5000000000    0.5000000000    0.3823529412    1.0
        0.5000000000    0.5000000000    0.4117647059    1.0
        0.5000000000    0.5000000000    0.4411764706    1.0
        0.5000000000    0.5000000000    0.4705882353    1.0
        0.5000000000    0.5000000000    0.5000000000    1.0

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