[QE-users] negative phonon frequencies for InAs in QE 6.5

[Sheikh Ziauddin Ahmed]

Hello

I am trying to compute the phonon frequencies ofI nAs. I am getting
negative frequencies near the gamma point. I also tried with epsil =.true.
But that does not change it. Here is the SCF and PH input I am using.

Please give me some suggestions on what I can do to fix this problem.

SCF:
 &control
    calculation='scf'
    restart_mode='from_scratch',
    prefix='test_i',
    pseudo_dir = '/InAs_phonon',
    outdir='./temp'
    tstress = .true. ,
    tprnfor = .true. ,
 /
 &system
    ibrav=2, celldm(1) =11.4485, nat=2, ntyp=2,
    ecutwfc = 50, ecutrho = 250
 /
 &electrons
    conv_thr    = 1.0e-9
    mixing_beta = 0.7
    mixing_mode = 'local-TF'
 /
ATOMIC_SPECIES
 In 114.818 In.pz-dn-kjpaw_psl.0.2.2.UPF
 As 74.92 As.pz-n-kjpaw_psl.0.2.UPF
ATOMIC_POSITIONS {crystal}
 In 0.0 0.0 0.0
 As 0.25 0.25 0.25
K_POINTS automatic
6 6 6 0 0 0


PH:
 &inputph
    tr2_ph=1d-14
    prefix='test_i',
    ldisp=.true.
    !epsil=.true.
    nq1=3, nq2=3, nq3=3
    amass(1)=114.818
    amass(2)=74.92
    outdir='/scratch/sza9wz/'
    fildyn = 'test_i-3.dyn'
 /

Regards,
Sheikh Ahmed
University of Virginia
-- 
*Sheikh Ziauddin Ahmed *
PhD Candidate
Charles L. Brown Department of Electrical and Computer Engineering
University of Virginia
Email:sza9wz*@virginia.edu* <sza9wz at virginia.edu>
LinkedIn: https://www.linkedin.com/in/sheikh-ziauddin-ahmed
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20200116/d1fc2101/attachment.html>