Maybe your computed gap is very small (and smaller than the experimental
one)?
Paolo
On 12/23/2025 1:03 PM, Vahid Askarpour wrote:
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
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216
_______________________________________________________________________________
The Quantum ESPRESSO Foundation stands in solidarity with all civilians
worldwide who are victims of terrorism, military aggression, and indiscriminate
warfare.
--------------------------------------------------------------------------------
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
