[Pw_forum] How to get band structure with hse correction in pwscf?

[Giuseppe Mattioli]

Dear Clarence
You can only perform scf calculations with EXX, so you must find a workaround. Let us suppose that your calculation is converged with this mesh

K_POINTS {automatic}
8, 8, 8, 0, 0, 0

In the pw output you find the K_POINTS {tpiba} trasformation of your automatic mesh, that is

     number of k points=    29  gaussian smearing, width (Ry)=  0.0100
                       cart. coord. in units 2pi/alat
        k(    1) = (   0.0000000   0.0000000   0.0000000), wk =   0.0039062
        k(    2) = (  -0.1250000   0.1250000  -0.1250000), wk =   0.0312500
        k(    3) = (  -0.2500000   0.2500000  -0.2500000), wk =   0.0312500
        k(    4) = (  -0.3750000   0.3750000  -0.3750000), wk =   0.0312500
        k(    5) = (   0.5000000  -0.5000000   0.5000000), wk =   0.0156250
        k(    6) = (   0.0000000   0.2500000   0.0000000), wk =   0.0234375
        k(    7) = (  -0.1250000   0.3750000  -0.1250000), wk =   0.0937500
        k(    8) = (  -0.2500000   0.5000000  -0.2500000), wk =   0.0937500
        k(    9) = (   0.6250000  -0.3750000   0.6250000), wk =   0.0937500
        k(   10) = (   0.5000000  -0.2500000   0.5000000), wk =   0.0937500
        k(   11) = (   0.3750000  -0.1250000   0.3750000), wk =   0.0937500
        k(   12) = (   0.2500000   0.0000000   0.2500000), wk =   0.0468750
        k(   13) = (   0.0000000   0.5000000   0.0000000), wk =   0.0234375
        k(   14) = (  -0.1250000   0.6250000  -0.1250000), wk =   0.0937500
        k(   15) = (   0.7500000  -0.2500000   0.7500000), wk =   0.0937500
        k(   16) = (   0.6250000  -0.1250000   0.6250000), wk =   0.0937500
        k(   17) = (   0.5000000   0.0000000   0.5000000), wk =   0.0468750
        k(   18) = (   0.0000000   0.7500000   0.0000000), wk =   0.0234375
        k(   19) = (   0.8750000  -0.1250000   0.8750000), wk =   0.0937500
        k(   20) = (   0.7500000   0.0000000   0.7500000), wk =   0.0468750
        k(   21) = (   0.0000000  -1.0000000   0.0000000), wk =   0.0117188
        k(   22) = (  -0.2500000   0.5000000   0.0000000), wk =   0.0937500
        k(   23) = (   0.6250000  -0.3750000   0.8750000), wk =   0.1875000
        k(   24) = (   0.5000000  -0.2500000   0.7500000), wk =   0.0937500
        k(   25) = (   0.7500000  -0.2500000   1.0000000), wk =   0.0937500
        k(   26) = (   0.6250000  -0.1250000   0.8750000), wk =   0.1875000
        k(   27) = (   0.5000000   0.0000000   0.7500000), wk =   0.0937500
        k(   28) = (  -0.2500000  -1.0000000   0.0000000), wk =   0.0468750
        k(   29) = (  -0.5000000  -1.0000000   0.0000000), wk =   0.0234375

Then you can copy this mesh in a new scf input and you can add further points with wk=0.0 (they do not contribute to the potential but you can use the 
corresponding eigenvalues to draw a coarse band structure).

K_POINTS {tpiba}
31 <-- 29+2 added
 0.0000000   0.0000000   0.0000000   0.0039062
-0.1250000   0.1250000  -0.1250000   0.0312500
-0.2500000   0.2500000  -0.2500000   0.0312500
-0.3750000   0.3750000  -0.3750000   0.0312500
 0.5000000  -0.5000000   0.5000000   0.0156250
 0.0000000   0.2500000   0.0000000   0.0234375
-0.1250000   0.3750000  -0.1250000   0.0937500
-0.2500000   0.5000000  -0.2500000   0.0937500
 0.6250000  -0.3750000   0.6250000   0.0937500
 0.5000000  -0.2500000   0.5000000   0.0937500
 0.3750000  -0.1250000   0.3750000   0.0937500
 0.2500000   0.0000000   0.2500000   0.0468750
 0.0000000   0.5000000   0.0000000   0.0234375
-0.1250000   0.6250000  -0.1250000   0.0937500
 0.7500000  -0.2500000   0.7500000   0.0937500
 0.6250000  -0.1250000   0.6250000   0.0937500
 0.5000000   0.0000000   0.5000000   0.0468750
 0.0000000   0.7500000   0.0000000   0.0234375
 0.8750000  -0.1250000   0.8750000   0.0937500
 0.7500000   0.0000000   0.7500000   0.0468750
 0.0000000  -1.0000000   0.0000000   0.0117188
-0.2500000   0.5000000   0.0000000   0.0937500
 0.6250000  -0.3750000   0.8750000   0.1875000
 0.5000000  -0.2500000   0.7500000   0.0937500
 0.7500000  -0.2500000   1.0000000   0.0937500
 0.6250000  -0.1250000   0.8750000   0.1875000
 0.5000000   0.0000000   0.7500000   0.0937500
-0.2500000  -1.0000000   0.0000000   0.0468750
-0.5000000  -1.0000000   0.0000000   0.0234375
 0.1000000   0.1000000   0.1000000   0.0000000 <-- added
 0.2000000   0.2000000   0.2000000   0.0000000 <-- added

However, remember that:

1) You pay for such additional k-points. Don't be too lavish!
2) You must use a minimal q-point mesh
    nqx1=1, nqx2=1, nqx3=1
because k+q  must be equivalent to some other k in the k-points list. If the cell is small this can lead to unconverged results.

HTH
Giuseppe


On Friday, May 12, 2017 04:42:37 AM LEUNG Clarence wrote:
> Dear QE users,
> 
> 
> HSE doesn't allow nscf calculations.
> 
> How to get band structure with hse correction in pwscf?
> 
> 
> Many thanks.
> 
> 
> Clarence
> 
> City University of Hong Kong

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   Giuseppe Mattioli                            
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