Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

ANAND JHA Thu, 03 Aug 2023 20:15:05 -0700

C parameter and a parameter are wrong they are too high and low

On Thu, 3 Aug 2023 at 20:01, Giuseppe Scala <g.sca...@campus.unimib.it> wrote:

Hi ANAND,

Would you mind if I ask you to tell me where's the problem in the structure? Maybe that c parameter is too high or low?
Il gio 3 ago 2023, 12:58 ANAND JHA <anandk...@iitk.ac.in> ha scritto:
There is some issue in your bilayer
Try to make a new bilayer with CRYSTAL SOFTWARE

On Thu, 3 Aug 2023 at 03:55, Giuseppe Scala <g.sca...@campus.unimib.it> wrote:
I get negative frequencies at gamma points for Bilayer MoS2. I relaxed my structure and checked convergence with respect to energy cutoff. That's my input file for the scf calculation:

##############

&CONTROL
calculation ='scf'
prefix = 'MoS2_BI'
pseudo_dir = '/home/Giuseppe'
outdir = './'
tstress = .true.
tprnfor = .true.
forc_conv_thr = 1.0d-3
nstep = 200
/

&SYSTEM
ibrav = 4
a = 3.1429635960300000000
c = 20.006663000000000000
nat = 6
ntyp = 2
ecutwfc = 60
ecutrho = 240
occupations = 'smearing'
degauss = 0.01
/

&ELECTRONS
mixing_beta = 0.7
conv_thr = 1.0d-8
diagonalization = 'david'
electron_maxstep=200
/

&IONS
trust_radius_max = 0.2
/
&CELL
cell_dynamics = "bfgs"
cell_dofree = '2Dxy'
/

ATOMIC_SPECIES
Mo 95.9400 Mo.pbesol-spn-kjpaw_psl.1.0.0.UPF
S 32.0660 S.pbesol-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS {angstrom}
Mo 1.5714815237 0.9072955423 6.6890512735
Mo 0.0000000000 1.8145901001 13.377562735
S 1.5714815237 0.9072955423 11.825385701
S 1.5714815237 0.9072955423 14.928508325
S 0.0000000000 1.8145901001 8.2412092563
S 0.0000000000 1.8145901001 5.1381015776

K_POINTS {automatic}
4 4 4 0 0 0

#########

And here my input file for ph.x

#######

&inputph
prefix = 'MoS2_BI'
fildvscf = 'dvscf'
ldisp = .true.
fildyn = 'MoS2_BI.dyn'
alpha_mix(1) = 0.3
nq1 = 2,
nq2 = 2,
nq3 = 2,
tr2_ph = 1.0d-12
/
########

Is my bilayer wrong? I've come the exact same calculations for Bulk and Monolayer MoS2 and everything went smoothly

_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users

_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users

Re: [QE-users] Negative frequencies for phonon dispersion in Bilayer MoS2

Reply via email to