[Pw_forum] band gap from DOS for LaFeO3

[Isaac Wiafe Boateng]

Dear All,
I am trying to calculate for the band gap of LaFeO3 which is antiferromagnetic. 

The spin polarization is described using spin up (0.5) and spin down (-0.5) as shown below in the &SYSTEM namelist. 


 &SYSTEM
       ibrav = 0,
       celldm(1) = 1.88972599,
       nat = 22,
       ntyp = 5,
       ecutwfc = 30,
       ecutrho = 180,
       occupations='smearing',
       smearing='fermi-dirac',
       degauss=0.003,
       nbnd=110
       nspin=2,
       starting_magnetization(1)=0.5,
       starting_magnetization(2)=-0.5,


After running scf and nscf calculations, the nscf output from which the eigenvalue gap is read from generates two set of k bands at different k-paths; one for spin up and the other for spin down.
The eigenvalue gap (HOMO LUMO gap) obtained from each of the spins is slightly different. 

My concern here is that I am not sure which eigenvalue gap to choose. Almost all literature I have seen does not report the spin state from which that value was calculated from.
Any advise please!!!!!!
Thanks
Isaac


 ..
Isaac Wiafe Boateng |Graduate Student 
Department of Chemistry, Theoretical and Computational Chem. Lab
KNUST, Kumasi - Ghana
+233 (0) 275 632712
Alt. e-mail: boatengisaacwiafe at gmail.com
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