I would give a shot to local-TF, mixing-beta not too small (~ 0.3).
is it a metal ? does increasing degauss help ?
is this an instability related to the occupation of the U-projectors ?
does it converge if you if you remove U ?
does the fcc cell with 10 atoms converge ?
stefano
On 09/10/2015 09:03, 庞瑞(PANG Rui) wrote:
Dear Zhao
The most efficient way is reducing the mixing_beta, you may try 0.1
-0.01 or even smaller if you can afford the CPU time. Is 50 enough for
O? You may check it, the smallest value usually is given in the PP
file. A personal experience is that do not use semi-core PP. I do not
understand the reason but I seldom get convergence when using
semi-core PPs in periodical cases with PWSCF.
Good luck
------------------
庞瑞 (PANG Rui)
South University of Science and Technology of China/Department of Physics
No.1088,Xueyuan Road, Shenzhen,Guangdong
------------------ Original ------------------
*From: * "Shuai"<zhao-sh...@edu.life.kyutech.ac.jp>;
*Date: * Fri, Oct 9, 2015 12:00 PM
*To: * "PWSCF Forum"<pw_forum@pwscf.org>;
*Subject: * [Pw_forum] Convergence NOT achieved for Sr2MnMoO6 using PAW pp
Dear User:
I am doing the SCF calculation of Sr2MnMoO6 using PAW Potentials but it
cannot converged.
I checked different Ecut (30Ry, 40Ry or 50Ry), mixing mode (TF or
plain), diagonalization (david or cg) and mixing_beta (0.3, 0.7), but it
always not converged.
The SCF input is:
&control
calculation = 'scf'
prefix = 'Sr2MnMoO6'
restart_mode = 'from_scratch'
pseudo_dir = '/'
outdir = '/'
/
&system
ibrav = 1
celldm(1) = 15.27295
nat = 40
ntyp = 4
ecutwfc = 50
ecutrho = 600
occupations = 'smearing'
smearing = 'mp'
degauss = 0.01
lda_plus_u = .true.
Hubbard_U(2) = 4.0
/
&electrons
conv_thr = 1e-8
mixing_mode = 'TF'
mixing_beta = 0.7
diagonalization = 'david'
/
ATOMIC_SPECIES
Sr 87.620 Sr.pbe-spn-kjpaw_psl.1.0.0.UPF
Mn 54.938 Mn.pbe-spn-kjpaw_psl.1.0.0.UPF
Mo 95.960 Mo.pbe-spn-kjpaw_psl.1.0.0.UPF
O 15.999 O.pbe-n-kjpaw_psl.1.0.0.UPF
ATOMIC_POSITIONS (crystal)
Sr 0.0000 0.0000 0.0000
Sr 0.5000 0.0000 0.0000
Sr 0.0000 0.5000 0.0000
Sr 0.5000 0.5000 0.0000
Sr 0.0000 0.0000 0.5000
Sr 0.5000 0.0000 0.5000
Sr 0.0000 0.5000 0.5000
Sr 0.5000 0.5000 0.5000
Mn 0.2500 0.2500 0.2500
Mo 0.7500 0.2500 0.2500
Mo 0.2500 0.7500 0.2500
Mn 0.7500 0.7500 0.2500
Mo 0.2500 0.2500 0.7500
Mn 0.7500 0.2500 0.7500
Mn 0.2500 0.7500 0.7500
Mo 0.7500 0.7500 0.7500
O 0.2500 -0.0140 0.2500
O -0.0140 0.2500 0.2500
O 0.2500 0.2500 -0.0140
O 0.7500 0.0140 0.2500
O 0.5140 0.2500 0.2500
O 0.7500 0.2500 0.0140
O 0.2500 0.5140 0.2500
O 0.0140 0.7500 0.2500
O 0.2500 0.7500 0.0140
O 0.7500 0.4860 0.2500
O 0.4860 0.7500 0.2500
O 0.7500 0.7500 -0.0140
O 0.2500 0.0140 0.7500
O 0.0140 0.2500 0.7500
O 0.2500 0.2500 0.5140
O 0.7500 -0.0140 0.7500
O 0.4860 0.2500 0.7500
O 0.7500 0.2500 0.4860
O 0.2500 0.4860 0.7500
O -0.0140 0.7500 0.7500
O 0.2500 0.7500 0.4860
O 0.7500 0.5140 0.7500
O 0.5140 0.7500 0.7500
O 0.7500 0.7500 0.5140
K_POINTS (automatic)
4 4 4 1 1 1
Thanks in advance for your suggestions.
Best regards,
Shuai Zhao
--
PhD candidate
Graduate School of Life Science and Systems Engineering
Kyushu Institute of Technology, Japan
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