CASTEP > Tasks in CASTEP > Setting up CASTEP calculations > Requesting electronic, structural, and vibrational properties > Requesting band structure

Requesting band structure

Calculating band structure properties produces electronic energies along high symmetry directions in the Brillouin zone. The standard path for each lattice type is taken from Bradley and Cracknell (1972). The path can be modified using the CASTEP Band Structure Options dialog. The density of points along the path, which affects the appearance of the resulting chart, can be controlled by the selection for the k-point set dropdown list or the approximate k-point separation can be manually specified in the Separation text box, in Å-1, on the Properties tab of the CASTEP Calculation dialog. Conduction band states can be included by specifying a nonzero value in the Empty bands text box on the same tab.

You are not required to use the same exchange-correlation functional in the band structure calculation as in the main calculation. This allows you to select a nonlocal screened-exchange functional to study the electronic structure after performing, for example geometry optimization with a variable cell using the GGA functional.

CASTEP does not support the use of nonlocal functionals (screened exchange, exact exchange, etc.) for ultrasoft pseudopotentials, i.e., nonlocal functionals can only be requested if all the pseudopotentials for the calculation are specified as norm-conserving.

To calculate band structure

  1. Choose Modules | CASTEP | Calculation from the Materials Studio menu bar.
  2. Select the Properties tab.
  3. Check the Band structure option on the Properties list.
  4. If necessary, modify the Number of empty bands to include more or less states in the conduction band.
  5. Optionally, adjust the density of k-points along the high symmetry directions by using k-point set dropdown list.
  6. Click the More... button to open the CASTEP Band Structure Options dialog.
  7. Click the Path... button to open the Brillouin Zone Path dialog. This dialog allows you to inspect and modify the Brillouin zone path used for the band structure calculation.
  8. On the CASTEP Band Structure Options dialog check the Use separate XC functional for band structure calculation checkbox to use a nonlocal functional for the electronic structure calculation.
  9. Select the alternative Functional you wish to use from the dropdown list.
See Also:

Mulliken population analysis
Hirshfeld charge analysis
Phonon density of states
Density of states and partial density of states
Optical properties
CASTEP Calculation dialog

Accelrys Materials Studio 8.0 Help: Wednesday, December 17, 2014
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