[QE-users] surface band structure of Au(111)

[BARRETEAU Cyrille]

Hi Imane


If you want to know about surface physics you should first read a good book.

I recommend: "Concepts in Surface Physics" by M.C. Desjonquères and D. Spanjaard.


As for the modelling in DFT: surfaces are usually described by "slabs".

Your input file looks fine expect that you did not consider the primitive cell of Au(111).

You are using a rectangular surface cell (with 2 atoms) while you should use the hexagonal one.

Your structure is correct but there is no reason (else you have something specific in mind) to double the unit-cell.

If you are interested in surface bands you should also use much more layers!

3 layers is clearly not enough, especially if you want to get the Shockley states correctly.


Good luck


Cyrille



________________________________
Cyrille Barreteau
CEA Saclay, IRAMIS, SPEC Bat. 771
91191 Gif sur Yvette Cedex, FRANCE
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+33 1 69 08 38 56 /+33  6 47 53 66 52  (mobile)
email:     cyrille.barreteau at cea.fr
Website:     http://iramis.cea.fr/Pisp/cyrille.barreteau/
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De : users <users-bounces at lists.quantum-espresso.org> de la part de imane BEZZAOUI <imane.bezzaoui at ump.ac.ma>
Envoyé : mardi 11 octobre 2022 19:58:18
À : users at lists.quantum-espresso.org
Objet : [QE-users] surface band structure of Au(111)

Dear All,

I am interested in calculating the surface band structure and I am also familiar with how to calculate the band structure of bulk material.
My questions are:

1) How does the surface band structure calculation differ from a bulk calculation?
4) how I choose my k-points high symmetry directions because when I used materials clouds,  didn't give me band structure  like in literature
and i would calculate the band structure in that direction K-G-M-K but i can't set right k-points high symmetry directions,
/////
scf.in<http://scf.in>
////
Au(111) surface with 3 layers ,I already did test of convergence of Ecut and kp-t and vacuum
/////
&CONTROL
  calculation = 'scf'
  outdir = './'
  prefix = 'au'
  pseudo_dir = './'
  tprnfor = .true.
  tstress = .true.
  verbosity = 'high'
restart_mode='restart',
/
&SYSTEM
  degauss =   1.4699723600d-02
  ecutrho =   1.8000000000d+02
  ecutwfc =   25
  ibrav = 0
  nat = 6
  ntyp = 1
/
&ELECTRONS
  conv_thr =   1.0800000000d-08
  electron_maxstep = 80
  mixing_beta =   4.0000000000d-01
  /
ATOMIC_SPECIES
Au     196.966569 Au.pbe-n-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS crystal
Au           0.0000000000       0.0000000000       0.0000000000
Au          -0.0000000000       0.6666670000       0.3920030000   0   0   1
Au          -0.0000000000       0.3333330000       0.1960010000
Au           0.5000000000       0.1666670000       0.3920030000   0   0   1
Au           0.5000000000       0.8333330000       0.1960010000
Au           0.5000000000       0.5000000000       0.0000000000
K_POINTS automatic
4 4 1 0 0 0
CELL_PARAMETERS angstrom
      2.9132800000       0.0000000000       0.0000000000
     -0.0000007045       5.0459490000       0.0000000000
      0.0000000000       0.0000000000      12.1360490000
Thanks very much for your help.
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