[Pw_forum] using quantum espresso by study of semiconductor Ta3N5

[Marcelo Castañeda]

I am using the QE for the study of the electronic properties of tantalum nitrate (Ta3N5). And please make the convergence tests for this system (E (cut) and K points). Proceeded to make the calculation of self-consistency (SCF), the calculation of non-self-consistency using the following pseudopotentials:N.pz-n-kjpaw_psl.0.1.UPFTa.pz-spn-kjpaw_psl.0.2.UPFTe input is: &CONTROL
                 calculation = 'scf',
                 restart_mode='from_scratch',
                 title       = 'Ta3N5',
                 prefix      = 'Ta3N5_exc1',
                 pseudo_dir  ='./pp',
                 verbosity   ='high', 
 /
 &SYSTEM
                      ibrav  = 9,
                   celldm(1) = 7.3567038029d0, 
                   celldm(2) = 2.6365270999d0, 
                   celldm(3) = 2.6365270999d0, 
                         nat = 16,
                        ntyp = 2,
                     ecutwfc = 160,
                     ecutrho = 960,
                   input_dft ='LDA',
                 occupations ='smearing',
                    smearing ='mv',
                     degauss =0.002d0,  
                 
/
 &electrons
    diagonalization ='david',
    mixing_beta     = 0.700d0,
 /
ATOMIC_SPECIES
   Ta   180.948000d0   Ta.pz-spn-kjpaw_psl.0.2.UPF
    N   14.0067000d0   N.pz-n-kjpaw_psl.0.1.UPF
ATOMIC_POSITIONS {crystal}
  Ta   0.1342900000d0   0.1342900000d0   0.5601000000d0
  Ta   0.8657100000d0   0.8657100000d0   0.0601000000d0
  Ta   0.8657100000d0   0.8657100000d0   0.4399000000d0
  Ta   0.1342900000d0   0.1342900000d0   0.9399000000d0
  Ta   0.2975700000d0   0.2975700000d0   0.2500000000d0
  Ta   0.7024300000d0   0.7024300000d0   0.7500000000d0
   N   0.7627000000d0   0.7627000000d0   0.2500000000d0
   N   0.2373000000d0   0.2373000000d0   0.7500000000d0
   N   0.0470000000d0   0.0470000000d0   0.1188000000d0
   N   0.9530000000d0   0.9530000000d0   0.6188000000d0
   N   0.9530000000d0   0.9530000000d0   0.8812000000d0
   N   0.0470000000d0   0.0470000000d0   0.3812000000d0
   N   0.3097000000d0   0.3097000000d0   0.0732000000d0
   N   0.6903000000d0   0.6903000000d0   0.5732000000d0
   N   0.6903000000d0   0.6903000000d0   0.9268000000d0
   N   0.3097000000d0   0.3097000000d0   0.4268000000d0
K_POINTS (automatic)
6 6 6 1 1 1
The result for the calculation of total state density no energy gap (experimentally this has a gap of 2.1 eV). The part I do not understand very well is the related variables: occupation, smearing and degauss.What values are suitable for the study of a semiconductor ?.Very grateful for the answer.
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