[QE-users] Dielectric constant of Bi2Te3 from ph.x seems too large

[Vahid Askarpour]

Dear QE Community,

When doing ph.x calculation on the bulk Bi2Te3 with qe-7.3.1, I get the following for the dielectric constant 

     
End of electric fields calculation
Dielectric constant in cartesian axis 

(     492.092803103       0.000000000      -0.000000000 )
(       0.000000000     492.092803103      -0.000000000 )
(       0.000000000      -0.000000000     100.437749350 )

The preliminary scf calculation was done with the following scf.in

&control
    calculation='scf',
    restart_mode='from_scratch',
    prefix='Bi2Te3',
    pseudo_dir='./'
    verbosity='high',
    tprnfor=.true.,
    tstress=.true.,
    etot_conv_thr=1.0d-6
    forc_conv_thr=1.0d-5
/
&system
    ibrav=0,
    nat=5, ntyp= 2, 
    ecutwfc = 110,
    occupations='fixed'
    lspinorb= .true.
    noncolin=.true.
/
&electrons
    diagonalization='cg'
    conv_thr = 1.0e-10
    mixing_beta = 0.5
    electron_maxstep = 500
    mixing_mode = 'plain'
/
ATOMIC_SPECIES
Bi 208.9804  Bi-d_r.upf
Te 127.6     Te-d_r.upf
CELL_PARAMETERS (angstrom)
     2.19309263036978    -1.26618262050178   10.15655859709168
     0.00000000000000     2.53236524100356   10.15655859709168
    -2.19309263036978    -1.26618262050178   10.15655859709168
ATOMIC_POSITIONS (crystal)
Bi   0.40035000000000   0.40035000000000   0.40035000000000
Bi   0.59965000000000   0.59965000000000   0.59965000000000
Te   0.20882000000000   0.20882000000000   0.20882000000000
Te   0.79118000000000   0.79118000000000   0.79118000000000
Te   0.00000000000000   0.00000000000000   0.00000000000000

K_POINTS (automatic)
12 12 12 0 0 0

I expected dielectric constants around 50. I am not sure if I am making a mistake or if this is a bug. Any suggestion is appreciated.

Thanks,

Vahid

Vahid Askarpour
Department of Physics and Atmospheric Science
Dalhousie University
Halifax, Canada