the gaussian smearing contribution is non-zero hence your system is not an insulator but has a non-zero DOS at the Fermi energy. are you sure that the structure is ok? I dont know why it is so and why the integrated dos around EF does not equal nelec... how is your input for the dos ? are you using the same number of points and the same smearing width ?
stefanno Nguyen Doan Sau wrote: > Hi there, > I have a problem related to DOS at fermi level. Let me start with my scf file > first > ------------- > &system > ibrav=0, celldm(1)=0 , nat=22, ntyp=4, > ecutwfc =37.0, occupations='smearing', smearing='gauss', degauss=0.01, > nelec=156 > nspin= 1, > / > &electrons > electron_maxstep= 300 > mixing_mode = 'plain' > mixing_beta = 0.2 > conv_thr = 1.0d-6 > diagonalization= 'david' > / > -------------- > My pseudopotentials are norm conversing, which are generated by ld1.x and > their transferability is OK. > here is the output > ---------- > the Fermi energy is 3.4391 ev > > ! total energy = -1213.21835062 Ry > Harris-Foulkes estimate = -1213.21835085 Ry > estimated scf accuracy < 0.00000034 Ry > > The total energy is the sum of the following terms: > > one-electron contribution = -711.80653324 Ry > hartree contribution = 352.57845405 Ry > xc contribution = -222.78424774 Ry > ewald contribution = -631.18916691 Ry > smearing contrib. (-TS) = -0.01685678 Ry > > convergence has been achieved in 32 iterations > ---------------------- > and Dos > 3.000 0.2551E+02 0.1178E+03 > 3.100 0.2931E+02 0.1207E+03 > 3.200 0.3391E+02 0.1241E+03 > 3.300 0.3375E+02 0.1275E+03 > 3.400 0.2724E+02 0.1302E+03 > 3.500 0.2299E+02 0.1325E+03 > 3.600 0.2335E+02 0.1348E+03 > 3.700 0.2043E+02 0.1369E+03 > 3.800 0.1297E+02 0.1381E+03 > 3.900 0.9369E+01 0.1391E+03 > 4.000 0.8969E+01 0.1400E+03 > > -------------- > My question are concerned to: > + DOS is still not zero at fermi level E=3.4391 > + Integrated DOS is not equal number of electron (156) , even I try > DeltaE=0.001 > ------------- > I have thought about the question > +First, My compound is insulator, an oxide with optical bandgap of 4 eV. But > in scf input, I use occupations='smearing'. Shoud I change it to > occupations='fixed' and increase nbnd>156/2 and delete smearing variable. > ------------ > Is there anyone had this problem before and please help me to fix that. > > Sau Nguyen > U of Houston > > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
