exercises:2014_ethz_mmm:bs
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exercise:bs [2014/05/20 08:18] – pshinde | exercises:2014_ethz_mmm:bs [2020/08/21 10:15] (current) – external edit 127.0.0.1 | ||
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$ module load espresso/ | $ module load espresso/ | ||
- | 2. Create a new directory and copy all the files from / | + | 2. Create a new directory and download |
**Self-Consistent Field (SCF) calculation: | **Self-Consistent Field (SCF) calculation: | ||
Line 42: | Line 42: | ||
$ grep “Fermi energy” | $ grep “Fermi energy” | ||
- | 6 10. For density of states | + | 6. Copy the mol.save directory to scf-mol.save. The scf-mol.save is required for ' |
+ | $ cp -rf mol.save/ scf-mol.save/ | ||
+ | |||
+ | **Non-Self-Consistent Field (NSCF) calculation: | ||
+ | |||
+ | In non-self-consistent calculation, | ||
+ | |||
+ | a) For finite geometries (e.g. molecules), where a single k-point (centre of BZ) is sufficient, the simple way is to perform self-consistent | ||
+ | |||
+ | b) For periodic geometries, a high quality DOS might require very fine meshes and for large cells one might need many k-points (depending on the system). Therefore, to save the computational time it is a good idea to calculate the self-consistent charge density with few k-points and then non-self-consistent calculation using fixed self-consistent charge density. | ||
+ | |||
+ | 7. For density of states calculation, do the non-self-consistent calculation using the input file " | ||
$ bsub -n 4 " mpirun pw.x < nscf.in > NSCF.out " | $ bsub -n 4 " mpirun pw.x < nscf.in > NSCF.out " | ||
- | 11. At the end, use dos.in input file to get the density of states from -20 to 10 eV. First column of " | + | 8. and then use dos.in input file to get the density of states from -20 to 10 eV. |
$ bsub -n 4 " mpirun dos.x < dos.in > DOS.out " | $ bsub -n 4 " mpirun dos.x < dos.in > DOS.out " | ||
- | 6. For band structure calculation, | + | First column of " |
+ | |||
+ | {{ graphene_dos.png? | ||
+ | |||
+ | 9. For band structure calculation, | ||
- | {{ : exercise:Graphene-BZ.png? | + | {{ Graphene-BZ.png? |
$ gcc –Wall kpoints.c –o kpoints | $ gcc –Wall kpoints.c –o kpoints | ||
Line 57: | Line 72: | ||
$ bsub -n 4 " mpirun pw.x < bands.in > BANDS.out " | $ bsub -n 4 " mpirun pw.x < bands.in > BANDS.out " | ||
- | 7. Ones the job is over, arrange the band energies according to the number of k-points. This means you need to write the data (from BANDS.out) | + | 10. Ones the job is over, arrange the band energies according to the number of k-points. This means you need to write the data (from BANDS.out) |
k = 0.0000 0.0000 0.0000 | k = 0.0000 0.0000 0.0000 | ||
Line 103: | Line 118: | ||
| | ||
- | 8. Use Qe_Bands.sh script to do this job | + | 11. Use Qe_Bands.sh script to do this job |
$ bash Qe_Bands.sh BANDS.out < | $ bash Qe_Bands.sh BANDS.out < | ||
- | 9. Plot (column 1 Vs column 2 of EnergyValues.txt) and save the band structure using gnu plot. Compare your band structure with the image provided here. The Fermi energy is set to zero. Do you see the linear dispersion of bands at K-point (+- 1 eV around the Fermi energy)? | + | 12. Plot (column 1 Vs column 2 of EnergyValues.txt) and save the band structure using gnu plot. Compare your band structure with the image provided here. The Fermi energy is set to zero. Do you see the linear dispersion of bands at K-point (+- 1 eV around the Fermi energy)? |
$ gnuplot plot_band.plt | $ gnuplot plot_band.plt | ||
- | {{ : exercise:Graphene-bands-reference.png? | + | {{ Graphene-bands-reference.png? |
- | |||
- | {{ : exercise: | ||
+ | 13. Before going for the different k-grid please delete all mol.save directories. | ||
+ | $ rm -rf mol.save/ | ||
+ | $ rm -rf scf-mol.save/ | ||
exercises/2014_ethz_mmm/bs.1400573923.txt.gz · Last modified: 2020/08/21 10:14 (external edit)