Hello everyone,
Iam doing DFT calculations on GaAs and wanted to check the results for the Monolayer and bilayer. So please guide me how to setup Monolayer and Bilayer in quantum espresso.
This is the input file:
&control
calculation='scf',
restart_mode='from_scratch',
outdir='./tmp',
prefix='gaas',
pseudo_dir='/home/abhi/src/espresso-5.2.1/pseudo/',
/
&system
ibrav=2,
celldm(1)=10.6827,
nbnd=8,
nat=2,
ntyp=2,
ecutwfc=20,
occupations='fixed',
/
&electrons
mixing_beta=0.7,
diagonalization='david'
/
ATOMIC_SPECIES
Ga 69.723 Ga.pbe-n-van.UPF
As 74.92160 As.pbe-n-van.UPF
ATOMIC_POSITIONS alat
Ga 0.0 0.0 0.0
As 0.25 0.25 0.25
K_POINTS automatic
12 12 12 0 0 0
Thanks,
Abhinav
For Graphene:
You have to put nat=2, because you have only two atoms in the unit cell, ntyp=1(only carbon atoms), celldm(1)=0.246nm(convert to Bohr), celldm(3)=c/a by taking v1 = a(1,0,0), v2 = a(-1/2,sqrt(3)/2,0), v3 = a(0,0,c/a). You should to fix the vacuo between two monolayers to avoid interaction.
ibrav=4,(hexagonal trigonal)
ATOMIC_SPECIES
C pseudopotential_you_want_to_use.UPF
ATOMIC_POSITIONS alat
C 0.0 0.0 0.0
C 0.0 -sqrt(3)/3 0.0
For Bilayer in Bernal stacking :
You have 4 carbon atoms in the unit cell, then ntyp=1, ntyp=1, celldm(1)=0.246nm(convert to Bohr), celldm(3)=c/a by taking v1 = a(1,0,0), v2 = a(-1/2,sqrt(3)/2,0), v3 = a(0,0,c/a). You should to increase the vacuo between two bilayers to avoid interaction.
ibrav=4,(hexagonal trigonal)
ATOMIC_SPECIES
C pseudopotential_you_want_to_use.UPF
ATOMIC_POSITIONS alat
C 0.0 0.0 0.0
C 1/2 -qsrt(3)/3 0.0
C 1/2 -sqrt(3)/2 c/a
C 0.0 0.0 c/a
The other parameters you have to fix.
Good luck!
Hello everyone...
Kindly tell is it possible to build nanocluster using Quantum Espresso..????
How to define the size of monolayer and bilayer in Quantum Espresso? How to relate the scf calculation with the experiment?
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