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Recipy for partially selfconsistent GW$_0$ calculations

In most cases, the ``best'' results (i.e. closest to experiment) are obtained by iterating only G, but keeping W fixed to the initial DFT W$_0$. This can be achieved in two manners. If the spectral method is not selected, the QP shifts are iterated automatically four times, and you will find four sets of QP shifts in the OUTCAR file. The first one corresponds to the G$_0$W$_0$ case, the final one to the GW$_0$ results. The INCAR file is simply:


 System  = Si
 NBANDS = 96
 ISMEAR = 0 ; SIGMA = 0.05
 ALGO = GW0 ; NOMEGA = 50
For technical reasons, it is not possible to iterate G in that manner, if LSPECTRAL=.TRUE. is set in the INCAR file. In this case, an iteration number must be supplied in the INCAR file using the NELM tag. Usually three to four iterations are sufficient for accurate QP shifts.

 System  = Si
 NBANDS = 96
 ISMEAR = 0 ; SIGMA = 0.05
 ALGO = GW0 ; NOMEGA = 50 
 NELM = 4
If the spectral method is not used, the specification of NELM is not sensible. If non diagonal components of the selfenergy should be included use ALGO = scGW0.


next up previous contents
Next: Using the GW routines Up: Frequency dependent GW calculations Previous: Recipy for selfconsistent GW   Contents
Georg Kresse
2007-03-01