update

2021.05.07_Quantum_Espresso/silicon/command.txt

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+pw.x < pw.scf.silicon_bands.in > pw.scf.silicon_bands.out
+
+pw.x < pw.bands.silicon.in > pw.bands.silicon.out
+
+bands.x < pp.bands.silicon.in > pp.bands.silicon.out
+
+python plot_bands.py

2021.05.07_Quantum_Espresso/silicon/plot_bands.py

@@ -0,0 +1,30 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+plt.rcParams["figure.dpi"]=150
+plt.rcParams["figure.facecolor"]="white"
+plt.rcParams["figure.figsize"]=(8, 6)
+
+# load data
+data = np.loadtxt('./si_bands.dat.gnu')
+
+k = np.unique(data[:, 0])
+bands = np.reshape(data[:, 1], (-1, len(k)))
+
+for band in range(len(bands)):
+    plt.plot(k, bands[band, :], linewidth=1, alpha=0.5, color='k')
+plt.xlim(min(k), max(k))
+
+# Fermi energy
+plt.axhline(6.6416, linestyle=(0, (5, 5)), linewidth=0.75, color='k', alpha=0.5)
+# High symmetry k-points (check bands_pp.out)
+plt.axvline(0.8660, linewidth=0.75, color='k', alpha=0.5)
+plt.axvline(1.8660, linewidth=0.75, color='k', alpha=0.5)
+plt.axvline(2.2196, linewidth=0.75, color='k', alpha=0.5)
+# text labels
+plt.xticks(ticks= [0, 0.8660, 1.8660, 2.2196, 3.2802], \
+           labels=['L', '$\Gamma$', 'X', 'U', '$\Gamma$'])
+plt.ylabel("Energy (eV)")
+plt.text(2.3, 5.6, 'Fermi energy')
+plt.savefig('si_bands.jpg')
+plt.show()

2021.05.07_Quantum_Espresso/silicon/pp.bands.silicon.in

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+&BANDS
+  prefix = 'silicon'
+  outdir = './tmp/'
+  filband = 'si_bands.dat'
+/
+
+K_POINTS {crystal_b}
+5
+  0.0000 0.5000 0.0000 20  !L
+  0.0000 0.0000 0.0000 30  !G
+  -0.500 0.0000 -0.500 10  !X
+  -0.375 0.2500 -0.375 30  !U
+  0.0000 0.0000 0.0000 20  !G

2021.05.07_Quantum_Espresso/silicon/pw.bands.silicon.in

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+&control
+  calculation = 'bands',
+  restart_mode = 'from_scratch',
+  prefix = 'silicon',
+  outdir = './tmp/'
+  pseudo_dir = '/opt/qe-7.3.1/pseudo'
+  verbosity = 'high'
+/
+
+&system
+  ibrav =  2,
+  celldm(1) = 10.2076,
+  nat =  2,
+  ntyp = 1,
+  ecutwfc = 50,
+  ecutrho = 400,
+  nbnd = 8
+ /
+
+&electrons
+  conv_thr = 1e-8,
+  mixing_beta = 0.6
+ /
+
+ATOMIC_SPECIES
+  Si 28.086  Si.pz-vbc.UPF
+
+ATOMIC_POSITIONS (alat)
+  Si 0.00 0.00 0.00
+  Si 0.25 0.25 0.25
+
+K_POINTS {crystal_b}
+5
+  0.0000 0.5000 0.0000 20  !L
+  0.0000 0.0000 0.0000 30  !G
+  -0.500 0.0000 -0.500 10  !X
+  -0.375 0.2500 -0.375 30  !U
+  0.0000 0.0000 0.0000 20  !G

2021.05.07_Quantum_Espresso/silicon/pw.scf.silicon_bands.in

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+&CONTROL
+  calculation = 'scf',
+  restart_mode = 'from_scratch',
+  prefix = 'silicon',
+  outdir = './tmp/'
+  pseudo_dir = '/opt/qe-7.3.1/pseudo'
+  verbosity = 'high'
+/
+
+&SYSTEM
+  ibrav =  2,
+  celldm(1) = 10.2076,
+  nat =  2,
+  ntyp = 1,
+  ecutwfc = 50,
+  ecutrho = 400,
+  nbnd = 8,
+!  occupations = 'smearing',
+!  smearing = 'gaussian',
+!  degauss = 0.005
+/
+
+&ELECTRONS
+  conv_thr = 1e-8,
+  mixing_beta = 0.6
+/
+
+ATOMIC_SPECIES
+  Si 28.086 Si.pz-vbc.UPF
+
+ATOMIC_POSITIONS (alat)
+  Si 0.0 0.0 0.0
+  Si 0.25 0.25 0.25
+
+K_POINTS (automatic)
+  8 8 8 0 0 0