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://pseudopotentials.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 &

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.