[Pw_forum] symmetry analysis in output of bands.x got a question mark for some band

[Andrea Dal Corso]

This is is not a bug. The symmetry analysis cannot be done if the
last wavefunction is a partner of a couple of degenerate bands,
and one of them has not been calculated.
If you need the symmetry label for that band you have to compute more bands.

Andrea


Quoting balabi <balabi at qq.com>:

> Dear developers,
>     I am calculating Bi2Se3, and I want to analyze the wave function
> parity on time reversal invariant momentum.
>
>     However I got some problem on k point Z
>
> xk=(   0.29758,   0.29758,   0.29758  )
>
>      Band symmetry, D_3d (-3m)  point group:
>
>      e(  1 -  2) =    -15.33381  eV     2   --> E_u  L_3'    
>  
>      e(  3 -  4) =    -15.33248  eV     2   --> E_g  L_3    
>   
>      e(  5 -  5) =    -15.32175  eV     1   --> A_1g L_1    
>   
>      e(  6 -  6) =    -15.31913  eV     1   --> A_2u L_2'    
>  
>      e(  7 -  8) =    -15.30954  eV     2   --> E_g  L_3    
>   
>      e(  9 - 10) =    -15.30659  eV     2   --> E_u  L_3'    
>  
>      e( 11 - 11) =     -6.45440  eV     1   --> A_1g L_1    
>   
>      e( 12 - 12) =     -5.91656  eV     1   --> A_2u L_2'      
>      e( 13 - 13) =     -4.53654  eV     1   --> A_1g L_1    
>   
>      e( 14 - 14) =     -2.62652  eV     1   --> A_2u L_2'      
>      e( 15 - 15) =     -0.80142  eV     1   --> A_1g L_1    
>   
>      e( 16 - 16) =      4.86845  eV     1   --> A_2u L_2'    
>  
>      e( 17 - 18) =      5.79799  eV     2   --> E_u  L_3'    
>  
>      e( 19 - 20) =      6.41406  eV     2   --> E_u  L_3'    
>  
>      e( 21 - 21) =      6.44464  eV     1   --> A_2u L_2'    
>  
>      e( 22 - 23) =      6.75173  eV     2   --> E_g  L_3    
>   
>      e( 24 - 24) =      7.00929  eV     1   --> A_1g L_1    
>   
>      e( 25 - 25) =      9.07355  eV     1   --> A_1g L_1    
>   
>      e( 26 - 27) =      9.43673  eV     2   --> E_g  L_3    
>   
>      e( 28 - 28) =      9.88292  eV     1   --> A_2u L_2'    
>  
>      e( 29 - 30) =     10.16254  eV     2   --> E_u  L_3'    
>  
>      e( 31 - 31) =     13.27098  eV     1   --> A_1g L_1    
>   
>      e( 32 - 32) =     14.41318  eV     1   -->   ?
>
> You can see the upper most band got "?" . Though I don't need parity of
> high energy band. But is this a bug?
>
> ----------------------------------------
> Below is my bands.in file
>
> &CONTROL
> prefix='Bi2Se3_SOC',
> calculation='bands',
> restart_mode='from_scratch',
> wf_collect=.true.,
> verbosity='high',
> outdir='/fs10/home/qhw_wang/HPC-nj/quantum_espresso/qe_tmpdir',
> pseudo_dir='/fs10/home/qhw_wang/HPC-nj/quantum_espresso/pseudo',
> /
> &SYSTEM
> ibrav = -5,celldm(1) =18.5969068371645,celldm(4)=0.9115970970052608,nat =
> 5,ntyp = 3,
> ecutwfc = 40,ecutrho = 500,
> noncolin=.true.,lspinorb=.true.,starting_magnetization=0.,
> nbnd=64,
> nosym=.true.,
> /
> &ELECTRONS
> conv_thr = 1.0d-10,  !default 1d-6
> diago_full_acc=.true.,!increase empty bands accuracy
> /
> ATOMIC_SPECIES
> Bi 208.98040  Bi.rel-pbe-dn-kjpaw_psl.0.2.2.UPF
> Se178.971Se.rel-pbe-n-kjpaw_psl.0.2.UPF
> Se278.971Se.rel-pbe-n-kjpaw_psl.0.2.UPF
> ATOMIC_POSITIONS crystal
> Bi0.39900.39900.3990
> Bi0.60100.60100.6010
> Se11.00001.00001.0000
> Se20.20600.20600.2060
> Se20.79400.79400.7940
> K_POINTS crystal_b
> 5
> 0.00000      0.00000      0.00000     1 !gG
> 0.50000      0.50000      0.50000     1 !Z
> 0.50000      0.50000     -0.00000     1 !F
> 0.00000      0.00000      0.00000     1 !gG
> 0.00000      0.00000     -0.50000     1  !L1