[Wien] Problem Regarding SLATER Calculations

[apande at iitk.ac.in]

Dear Wien2k users,I am doing the band gap of Ne(fcc) calculation using
Slater Potential and facing a problem. I am doing following steps:

1.	Generate  the structure
Neon: Ne  |space group : 225  |Lattice constant = 4.47A |Position(0,0,0)
RMT set automatically to 0%

2.	Initialize LAPW Calculation : initialize calc.
Select Spin Polarized Calculation
VXC option (default i.e. 13: PBE)
RKmax : 7 (default)

3.	Initialize hartree fock calculation : init_hf_lapw

  edit case.inhf

The initial file looked like

0.25	alpha
T	screened (T) or unscreened (F)
.165	lambda
xx	nband
6	gmax
3	lmaxe
3	lmaxv
1d-3	tolu

The file modified was

1	alpha
F	screened (T) or unscreened (F)
10	nband
6	gmax
3	lmaxe
3	lmaxv
1d-3	tolu

4.	Edit input file
In files the case.in0 was edited
XC_PBE was replaced by VX_SLATER (as mentioned in the user guide) . The
file was saved.

5.	SCF cycle
The command run_vnonlocal_lapw(-sp) was put in the command line and the
SCF cycle was initiated.

6.	Final Results
The calculations converged and the band gap came out to be : 10.813eV

7.THE PROBLEM
The band gap calculated deviates drastically from the value provided in
the following paper (ie 15.58).
How Close Are the Slater and Becke-Roussel Potentials in Solids?
-	F.Tran, P Blaha , K. Schwarz

 Neon has only been taken as an example to highlight the problem. The
deviation was still prominent in all the many others calculations
performed ( For eg Ar : 7.766 eV calculated , 9.95 eV according to the
paper.)


With Regards

Aditya Pande