How to calculate the Band structure of Silicon (MaX-5.1 version)

 

 To download and install MaX-5.1 version of Fleur code click on the following link:

How to download and install Fleur code (Version MaX-5.1)

To calculate the band structure of Silicon we proceed as follows:

First we create a directory called Si_band and change to it

algerien1970@linux-ml0a:~/abinitio/Fleur_tutorials> mkdir Si_band
algerien1970@linux-ml0a:~/abinitio/Fleur_tutorials> cd Si_band

we need the struct file called inpSi.txt  

alpha Si

&input film=f /

&lattice latsys=cF a0=2.67247737973 a=3.86709 /

2
14  0.125  0.125  0.125
14 -0.125 -0.125 -0.125

&kpt div1=3 div2=3 div3=3 tkb=0.0005 /

 

Creation of input file inp.xml using inpgen program

 

algerien1970@linux-ml0a:~/abinitio/Fleur_tutorials/Si_band> inpgen -f inpSi.txt 

      Welcome to FLEUR - inpgen   (www.flapw.de)   
      MaX-Release 5.1          (www.max-centre.eu)
 Processing k-point string:                                         
 Generating default k-point set
           8           8           8         512
 Processing k-point string: band=240                                
 Generating a k-point set for bandstructures with          240  k-points
 Stored k-point lists:
 
                NAME           TYPE      NKPT   COMMENT
 ================================================================================
             default           MESH        60   8 x 8 x 8
              path-2           PATH       240   X - K - g - L - W - X - g
 ================================================================================

 *****************************************
 Run finished successfully
 Stop message:
   All done
 *****************************************
Rank:0 used    0.041   0.006 GB/           42824 kB
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   436  100   101  100   335    194    646 --:--:-- --:--:-- --:--:--   645
Note: The following floating-point exceptions are signalling: IEEE_DENORMAL
STOP OK

 

We get the following output files 

algerien1970@linux-ml0a:~/abinitio/Fleur_tutorials/Si_band> ls
default.econfig  inpSi.txt  inp.xml  kpts.xml  out  scratch  struct.xsf  sym.xml  usage.json

 

Calculation

SCF calculation

algerien1970@linux-ml0a:~/abinitio/Fleur_tutorials/Si_band> fleur

========== k-point set info ==========
 Selected k-point list: default
 k-point list type: mesh
 8 x 8 x 8
 Number of k points: 60
 
 --------------------------------------------------------
 Number of OMP-threads:           4
 --------------------------------------------------------
 Iteration:           1  Distance:   8.3978763318531193     
 Iteration:           2  Distance:   7.9308061411190698     
 Iteration:           3  Distance:  0.92315692087222601     
 Iteration:           4  Distance:  0.53193789731964214     
 Iteration:           5  Distance:  0.21834356000472049     
 Iteration:           6  Distance:   2.0382807412186218E-002
 Iteration:           7  Distance:   1.3459539453815082E-002
 Iteration:           8  Distance:   1.3250797154136997E-003
 Iteration:           9  Distance:   1.8920853160491063E-003
 Iteration:          10  Distance:   1.7915187323775390E-004
 Iteration:          11  Distance:   4.6572139849496764E-005
 Iteration:          12  Distance:   9.4972035200838346E-006

 *****************************************
 Run finished successfully
 Stop message:
   all done
 *****************************************
Rank:0 used    0.264   0.019 GB/          338736 kB
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   837  100   101  100   736    206   1506 --:--:-- --:--:-- --:--:--  1505
Note: The following floating-point exceptions are signalling: IEEE_DENORMAL
STOP OK

 

BAND calculation 

Select the kpoint path suitable for band calculation from kpts.xml file. There are 1 mesh called default and 1 path called path-2 created by the inpgen program in kpts.xml file. Only the path is suitable for band calculation.

 

               NAME           TYPE      NKPT   COMMENT
 ================================================================================
             default           MESH        60   8 x 8 x 8
              path-2           PATH       240   X - K - g - L - W - X - g
 ================================================================================

We  select path-2 and add it in inp.xml file as follows:

<kPointListSelection listName="path-2"/>
         <!-- k-points included here -->
         <xi:include xmlns:xi="http://www.w3.org/2001/XInclude" href="kpts.xml"> </xi:include>
      </bzIntegration>

And we convert the band switch from F to T in the output element as follows:

 <output dos="F" band="T" slice="F">

 

Now we do a band calculation using fleur program 

algerien1970@linux-ml0a:~/abinitio/Fleur_tutorials/Si_band> fleur

 

Plotting

The band structure is in file band.gnu which we plot it using gnuplot program

algerien1970@linux-ml0a:~/abinitio/Fleur_tutorials/Si_band> gnuplot < band.gnu > bands.JPG

 

 

 https://www.flapw.de/downloads/WS2021/Workflow-talk.pdf