[QE-users] Problem using ph.x with DFPT+U in QE 6.4.(1)

[Timrov Iurii]

Dear Shenli Zhang,


> with an output error “forrtl: severe (174): SIGSEGV, segmentation fault occurred”


Was is printed in the output file of the PHonon calculation after the crash?


Check if you have enough RAM to run DFPT+U, because it is heavy.


Your input for a PW SCF calculation has some problem:

- ecutrho/ecutwfc = 4 - this is true for norm-conserving pseudopotentials. But you are using PAW, for which the ratio should be 8 or more. Try to use DFPT+U with ultrasoft pseudopotentials (the ratio should be also 8 or more).

- nbnd=50 - this is not needed: just remove it from the input file

- occupations='fixed' : is your system a nonmagnetic insulator? Did your PW SCF calculation converged successfully?

- conv_thr=1.0d-12 : I suggest to try conv_thr=1.0d-14 if you plan to compute phonons afterwards.


HTH


Regards,

Iurii


--
Dr. Iurii Timrov
Postdoctoral Researcher
STI - IMX - THEOS and NCCR - MARVEL
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of Shenli Zhang <shlzhang at uchicago.edu>
Sent: Tuesday, November 12, 2019 5:57:47 PM
To: users at lists.quantum-espresso.org
Subject: [QE-users] Problem using ph.x with DFPT+U in QE 6.4.(1)

Dear all,

I’m testing phonon calculations using ph.x with DFPT+U in QE 6.4 and QE 6.4.1, however the calculation always stops at the line “Calculating the dnsorth_cart matrix…”  with an output error “forrtl: severe (174): SIGSEGV, segmentation fault occurred”
I ran my system without U successfully. And I also ran the LiCoO2 +U example successfully. The only difference I can think of between my input file and the example file is the unit cell shape, where my LaCoO3 system has a rhombohedral unit cell and the example LiCoO2 has an orthorhombic one. Could this be a problem or did I make some mistakes?

Attached are the input files for my system LCO. Thank you!

SCF calculation input:
&control
    calculation='scf'
    prefix='LaCoO3p_relax'
    outdir=rhomb_U3
    pseudo_dir = '/home/shlzhang/QE_simulation/LaCoO3/pseudo',
/
&system
    nbnd=50
    ibrav=-5, celldm(1)=10.1352, celldm(4) =0.47876847, nat=10, ntyp= 3,
    ecutwfc =90, ecutrho =360, !for PAW ecutrho=4*ecutwfc, but need test
    occupations='fixed' !energy units in Ry
    lda_plus_u=.true.  Hubbard_U(2)=3
/
&electrons
conv_thr=1.0d-12
/
&ions
/
&cell
!cell_dofree='shape'
/
ATOMIC_SPECIES
La 138.9055 La.pbe-spfn-kjpaw_psl.1.0.0.UPF
Co 58.9332 Co.pbe-spn-kjpaw_psl.0.3.1.UPF
O  16 O.pbe-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS (crystal)
O        0.312627155   0.750000000   0.187372845
O        0.750000000   0.187372845   0.312627155
O        0.187372845   0.312627155   0.750000000
O        0.687372845   0.250000000   0.812627155
O        0.812627155   0.687372845   0.250000000
O        0.250000000   0.812627155   0.687372845
Co      -0.000000000   0.000000000  -0.000000000
Co       0.500000000   0.500000000   0.500000000
La       0.250000000   0.250000000   0.250000000
La       0.750000000   0.750000000   0.750000000
K_POINTS automatic
  4 4 4 0 0 0

Phonon calculation input:

phonons of bulk LaCoO3 at Gamma
&inputph
   prefix='LaCoO3p_relax'
   outdir=rhomb_U3
   fildyn='LaCoO3.dyn'
   max_seconds=82800
   tr2_ph=1.0d-14
   verbosity='debug'
   amass(1)=138.9055
   amass(2)=58.9332
   amass(3)=16
   epsil=.true.
   trans=.true.
/
0.00000000000 0.000000000000 0.000000000000000


--
Shenli Zhang
Postdoc
Pritzker School of Molecular Engineering
The University of Chicago
5640 South Ellis Avenue, Chicago, IL 60637
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