We need 2 files

si-dos.cell

%block lattice_abc
3.8 3.8 3.8
60 60 60
%endblock lattice_abc
!
! Atomic co-ordinates for each species.
! These are in fractional co-ordinates wrt to the cell.
!
%block positions_frac
Si 0.00 0.00 0.00
Si 0.25 0.25 0.25
%endblock positions_frac
!
! Analyse structure to determine symmetry
!
symmetry_generate
!
! Specify M-P grid dimensions for electron wavevectors (K-points)
!
kpoint_mp_grid 4 4 4

! Specify a uniform sampling of the Brillouin Zone
!
spectral_kpoint_mp_grid 17 17 17


si-dos.param

task            spectral      ! The TASK keyword instructs CASTEP what to do
spectral_task   dos           !
xc_functional   LDA           ! Which exchange-correlation functional to use.
cut_off_energy  500 eV        !
opt_strategy    speed         ! Choose algorithms for best speed

 

Note

There are 2 ways to use the pseudopotentials:

- Using an external pseudopotential with extention .usp

- Using an internal pseudopotential created by the code during the execution according to type mentioned  in the param file which we will do it in this tutorial.


Execution

For serial calculation

/Si-dos$ castep.serial si-dos

For parallel calculation 

/Si-dos$ mpirun -np 4 castep.mpi si-dos

 

We will get the following files

/Si-dos$ ls
Si_C19_LDA_OTF.usp  si-dos.bands  si-dos.castep      si-dos.cell   si-dos.cst_esp 
si-dos-out.cell  si-dos.0001.spec    si-dos.bib    si-dos.castep_bin  si-dos.check
si-dos.dome_bin  si-dos.param

 

Plotting 

/Si-dos$ dos.pl -xg si-dos.bands -w 0.3

 We will get the following picture