mirror of https://gitlab.com/QEF/q-e.git
44 lines
2.1 KiB
Plaintext
44 lines
2.1 KiB
Plaintext
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This example shows how to calculate the Density of States (DOS) and
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how to plot the Fermi Surface of Ni .
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The calculation proceeds as follows (for the meaning of the cited input
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variables see the appropriate INPUT_* file)
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1) make a self-consistent calculation for Ni (like in example 1).
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(input=ni.scf.in, output=ni.scf.out)
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2) make a band structure calculation for Ni (input=ni.dos.in,
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output=ni.dos.out) on a uniform k-point grid (automatically
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generated). In this example the Fermi level is calculated with the
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tetrahedra method (not in the actual band structure calculation but in
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the subsequent DOS calculation). If preferred, a gaussian broadening
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may be specified in this or in the subsequent step.
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3) the program dos.x reads file filpun (ni.pun) and calculates the DOS on a
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uniform grid of energies from Emin to Emax, with grid step Delta E.
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The output DOS is in file ni.dos, ready for plotting.
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4) the program projfwc.x projects the crystal wavefunctions on an
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orthogonalized basis set of atomic orbitals, calculates the Loewdin
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charges, spilling parameter, and the projected DOS (total DOS in file
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'ni.pdos_tot', s and d component in files 'ni.pdos_atm#1(Ni)_wfc#1(s)'
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and 'ni.pdos_atm#1(Ni)_wfc#2(d)' respectively). (input=ni.pdos.in,
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output=ni.pdos.in)
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5) Fermi Surface plot (updated version of the tools by Eyvaz Isaev):
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make again a self-consistent calculation,
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followed by a non-scf calculation ('nscf') with tetrahedra (smearing is
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also OK as long as the Fermi energy s computed) and a dense automatic
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(Monkhorst-Pack) unshifted grid, using
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K_POINTS automatic
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24 24 24 0 0 0
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Finally, run the "fs.x" utility, specifying in namelist &fermi the correct
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"outdir" and "prefix", optionally the output filename "filfermi" and
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"DeltaE" (see below). The code will select bands that cross the Fermi
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energy Ef+/-1eV (or Ef+/-DeltaE if specified) and write them into file,
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"filfermi"_fs.bxsf for spin-unpolarized, "filfermi"_fsup.bxsf and
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"filfermi"_fsdw.bxsf for spin-polarized calculations (filfermi=prefix
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is not specified). Plot these files using "xcrysden --bxsf"
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