Fermi Surfaces with Quantum Espresso

Here we consider just the Fermi surface of copper.

Running PWSCF to produce a detailed non self-consistent band structure is a two-stage process.

Stage 1

copper.in

&CONTROL
  calculation = 'scf',
  outdir = '.',
  pseudo_dir = '.'
/
&SYSTEM
  ibrav = 0,
  nat   = 1,
  ntyp  = 1,
  occupations = 'smearing',
  degauss = 0.01
  ecutwfc = 20
/
&ELECTRONS
/

CELL_PARAMETERS angstrom
 -1.7669227   0.0000000   1.7669227
  0.0000000   1.7669227   1.7669227
 -1.7669227   1.7669227   0.0000000

ATOMIC_SPECIES
  Cu   1.0   Cu.UPF

ATOMIC_POSITIONS angstrom
 Cu   0.000000000  0.000000000  0.000000000

K_POINTS automatic
  9 9 9 0 0 0

And, for the pseudopotential

$ curl -o Cu.UPF https://www.quantum-espresso.org/upf_files/Cu.pz-dn-rrkjus_psl.0.2.UPF

The PWSCF can be run to perform the self-consistent step with:

$ pw.x -in copper.in > copper.log

Stage 2

The band structure calculation requires an almost identical input file. Below, only the changed lines are given.

copper.bands.in

&CONTROL
  calculation = 'bands',

[...]

K_POINTS automatic
  45 45 45 0 0 0

This can then be run as:

$ pw.x -in copper.bands.in > copper.bands.log

and it will over-write much of the output from the SCF run.

Now c2x can be run as:

$ c2x --bxsf pwscf.xml copper.bxsf

and, for the sake of change, this example uses FermiSurfer, not XCrysDen, for the visualisation:

$ fermisurfer copper.bxsf &

Cu Fermi surface in FermiSurfer

Note that FermiSurfer numbers the bands from zero, not one, and that it colours the Fermi surface by the Fermi velocity (which it calculates).

Back to visualising Fermi surfaces.