quantum-espresso/PP/examples/example02

This example shows how to calculate the Density of States (DOS) and
how to plot the Fermi Surface of Ni .

The calculation proceeds as follows (for the meaning of the cited input
variables see the appropriate INPUT_* file)

1) make a self-consistent calculation for Ni (like in example 1).
   (input=ni.scf.in, output=ni.scf.out)

2) make a band structure calculation for Ni (input=ni.dos.in,
   output=ni.dos.out) on a uniform k-point grid (automatically
   generated). In this example the Fermi level is calculated with the
   tetrahedra method (not in the actual band structure calculation but in
   the subsequent DOS calculation). If preferred, a gaussian broadening
   may be specified in this or in the subsequent step.

3) the program dos.x reads file filpun (ni.pun) and calculates the DOS on a
   uniform grid of energies from Emin to Emax, with grid step Delta E.
   The output DOS is in file ni.dos, ready for plotting.

4) the program projfwc.x projects the crystal wavefunctions on an
   orthogonalized basis set of atomic orbitals, calculates the Loewdin
   charges, spilling parameter, and the projected DOS (total DOS in file
   'ni.pdos_tot', s and d component in files 'ni.pdos_atm#1(Ni)_wfc#1(s)'
   and 'ni.pdos_atm#1(Ni)_wfc#2(d)' respectively).  (input=ni.pdos.in,
   output=ni.pdos.in)

5) Fermi Surface plot (updated version of the tools by Eyvaz Isaev):
   make again a self-consistent calculation,
   followed by a non-scf calculation ('nscf') with tetrahedra (smearing is
   also OK as long as the Fermi energy s computed) and a dense automatic
   (Monkhorst-Pack) unshifted grid, using 
   K_POINTS automatic
   24 24 24 0 0 0
   Finally, run the "fs.x" utility, specifying in namelist &fermi the correct
   "outdir" and "prefix", optionally the output filename "filfermi" and
   "DeltaE" (see below). The code will select bands that cross the Fermi
   energy Ef+/-1eV (or Ef+/-DeltaE if specified) and write them into file,
   "filfermi"_fs.bxsf for spin-unpolarized, "filfermi"_fsup.bxsf and
   "filfermi"_fsdw.bxsf for spin-polarized calculations (filfermi=prefix
   is not specified). Plot these files using "xcrysden --bxsf"