[QE-users] geometry outimization under finite homogeneous electric field

[Maxim Arsentev]

Dear Quantum Espresso users,

I'm trying to perform geometry optimization runs with finite homogeneous 
electric field described through the modern theory of the polarization 
for the monolayer TiS2

Is it legitimate for such a system (it is not a dielectric)?, if not, 
what other methods are there for such a system?

Thank you, here is my code

  &control
     prefix='TiS3',
     calculation = 'relax',
     restart_mode = 'from_scratch'
     pseudo_dir='$PSEUDO_DIR',
     outdir = '$TMP_DIR',
     forc_conv_thr = 1.0d-3 ,
     !forc_conv_thr = 1.0d-2 ,
     nstep = 99,
     etot_conv_thr = 1.0d-4 ,
     !etot_conv_thr = 2.0d-10 ,
     lelfield=.true.,
     nberrycyc=3,
  /
  &system
     ibrav=  0, nat=  15, ntyp= 4,
     celldm(1)=1.889726,
     ecutwfc = 39.0, ecutrho = 300,
     !occupations ='smearing', smearing ='gaussian',
     !degauss=0.02,
     input_dft = 'vdW-DF',
  /
  &electrons
     conv_thr = 1e-6,
     mixing_beta=0.3,
     electron_maxstep=500,
     efield_cart(1)=0.d0,efield_cart(2)=0.d0,efield_cart(3)=0.050d0
  /
  &ions
  /
   &cell
    cell_factor = 1.5
  /
ATOMIC_SPECIES
   Ti  47.86700  Ti.pbe-spn-rrkjus_psl.0.3.1.UPF
    S  32.0660   S.pbe-n-rrkjus_psl.0.1.UPF
   Li   6.941    Li.pbe-s-rrkjus_psl.0.2.1.UPF
    H  1.007940  H.pbe-rrkjus_psl.0.1.UPF
ATOMIC_POSITIONS crystal
  H       0.213363000     0.178857000     0.243496000
  H       0.134546000     0.255217000     0.233180000
Li       0.233954000     0.175579000     0.132762000
Ti       0.980482000     0.008124000     0.995434000
Ti       0.487252000     0.007521000     0.996140000
Ti       0.235353000     0.505413000     0.995123000
Ti       0.735346000     0.515324000     0.995926000
  S       0.982820000     0.344132000     0.069262000
  S       0.487669000     0.343713000     0.069725000
  S       0.235891000     0.838631000     0.069596000
  S       0.735943000     0.843450000     0.068669000
  S       0.235788000     0.175732000     0.925965000
  S       0.735233000     0.176684000     0.925749000
  S       0.985574000     0.675253000     0.925626000
  S       0.485446000     0.675405000     0.925646000
CELL_PARAMETERS (alat)
    6.9649200000    0.0000000000    0.0000000000
    0.0000000000    6.0339600000    0.0000000000
    0.0000000000    0.0000000000   20.0000000000
K_POINTS {automatic}
  6 6 1 0 0 0