/QE-Tutorials

Tutorials for Q-MS School 2021

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Quantum Espresso Tutorials

Tutorials on Quantum Espresso for the Q-MS School 2021

GaAs: A direct gap semiconductor

  1. Run your first SCF calculation for GaAs
  2. Test convergence of the total energy against the k-point mesh
  3. Compute the equation of state (energy vs. volume):
  • Run a sequence of SCF calculations with different lattice parameter
  • Fit to the Murnaghan equation of state (code: ev.x) and compare to experiments
  1. Compute the bands and the electronic density of states.
  • How large is the band gap? Does it compare well to experiments?
  1. Repeat the band gap calculation using a hybrid functional (HSE): what happens to the band gap?

Al bulk: a metal

  1. Modify the GaAs input file to run SCF for Aluminum: does it work?
  2. Use smearing to achieve SCF and test k-points convergence
  3. Compute the equation of state (energy vs. volume) + Murnhagan Fit
  • Test the plane waves cutoff
  • Test the effect of the smearing
  1. Compute the bands and the electronic density of states

Al(111) surface

  1. Optimize the geometry of an Al (111) slab (4 layers thick)
  2. Compute the band diagram and the density of states of the slab

Challenge

Compute the adsorption energy of H2 on Al(111)

Hints:

  • Adsorption energy: Eads=E(Al(111)+H2)-E(Al(111))-E(H2)
  • Put H2 in atop position (see example NOT CONVERGED!!!)
  • Compute E(H2) in the same cell as Al(111)
  • Check convergence with PW cutoff and k-points