<div dir="ltr"><div><div><div><div>Dear Researchers,<br></div>I am trying to find out the effect of electric field in the band structure of two layers of graphene on diamond. I have relaxed the structure, and calculated the scf analysis when an electric field is applied. But the bizarre thing is that after scf calculation, it shows that the highest occupied level energy is greater than lowest unoccupied energy.<br>     highest occupied, lowest unoccupied level (ev):     3.8330    3.0227<br><br></div>Here is my input file:<br> &CONTROL<br>                 calculation = 'scf' ,<br>                restart_mode = 'from_scratch' ,<br>                      outdir = '/home/khalid/Desktop/WorkShop-QE/G-D/outdir' ,<br>                  pseudo_dir = '/home/khalid/Software/pseudo/' ,<br>                      prefix = '0V' ,<br>                   verbosity = 'high',<br>                     tprnfor = .true. ,<br>                          dt = 30.D0 ,<br>               forc_conv_thr = 0.5e-3,<br>                    lelfield = .true.,<br> /<br> &SYSTEM<br>                       ibrav = 4,<br>                           A = 2.500D0 ,<br>                           C = 35D0 ,<br>                         nat = 16,<br>                        ntyp = 2,<br>                        nbnd = 32,<br>                     ecutwfc = 40 ,<br>                     ecutrho = 320 ,<br>                    vdw_corr = 'Grimme-D2' ,<br><br> /<br> &ELECTRONS<br>                    conv_thr = 1.0D-8 ,<br>              diago_full_acc = .true. ,<br>              efield_cart(1) = 0.D0 ,<br>              efield_cart(2) = 0.D0 ,<br>              efield_cart(3) = 7.85773434152D-4,<br><br> /<br> &IONS<br>/<br>ATOMIC_SPECIES<br>    C   12.01070  C.pbe-rrkjus.UPF <br>    H    1.00079  H.pbe-rrkjus.UPF<br><br>ATOMIC_POSITIONS (crystal)<br>H        0.005327839   0.004936103  -0.039898089<br>C        0.004926444   0.004582078  -0.008232253<br>C        0.671599552   0.337923875   0.005766152<br>C        0.671768313   0.338081577   0.050081563<br>C        0.338481895   0.671502721   0.064811114<br>C        0.338691934   0.671979341   0.108893412<br>C        0.005421334   0.005439682   0.123645141<br>C        0.005667179   0.005902171   0.167715778<br>C        0.672369126   0.339318156   0.182472983<br>C        0.672346658   0.339452100   0.226746595<br>C        0.339014774   0.672791793   0.240795482<br>H        0.339023315   0.672405499   0.272371095<br>C        0.335828914   0.671897977   0.349302159<br>C        0.002522315   0.005282989   0.349302194<br>C        0.002566325   0.005331307   0.451725813<br>C        0.335878084   0.671955633   0.451725861<br>K_POINTS automatic <br>  12 12 1   1 1 1 <br> <br></div>Is it reasonable to have such kind of result? Did I do something wrong ?<br><br></div>Thanks in advance <br></div>