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Manual Pseudopotentials and orbitals Examples

 

4.6.3 Band structure


The task of this section explains how to calculate the energy band structure. The STRU file is the same with those in 4.6.2. The INPUT can be changed to:

 

INPUT_PARAMETERS
#Parameters (General)
suffix Si2_diamond
ntype 1
nbands 8
calculation nscf
#Parameters (Accuracy)
ecutwfc 50
niter 50
dr2 1.0e-9
ethr 1.0e-7
#Parameters (File)
start_charge file
out_band 1
#Parameters (Smearing)
smearing gaussian
sigma 0.02

 

New parameters in file INPUT:
out_band output the band structure.
Here the the relevant k-point file is no longer KPT, but rather KLINES. It looks like,

 

K_POINTS # keyword for start
6 # number of high symmetry lines
Line # line-mode
0.5 0.0 0.5 20 # X
0.0 0.0 0.0 20 # G
0.5 0.5 0.5 20 # L
0.5 0.25 0.75 20 # W
0.375 0.375 0.75 20 # K
0.0 0.0 0.0 1 # G

 

6 number of k points, here means 6 k points:
(0.5, 0.0, 0.5) (0.0, 0.0, 0.0) (0.5, 0.5, 0.5) (0.5, 0.25, 0.75) (0.375, 0.375, 0.75) (0.0, 0.0, 0.0)

20/1 number of k points along the segment line, which is constructed by two adjacent k points.

 

Run the program, and you will see a file named BANDS_1.dat in the output directory. Plot it to get energy band structure.

 

 

 

 

 

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