Dear siesta community:
I am having trouble to get a SCF calculation converged for a layered composite
system. Can somebody give me a hand?
Our system is "graphene n layers on top of Ni(111) surface". I am using GGA
pseudopotentials for Ni and C elements. When a simplest SZ basis set is used,
SCF calculation can converge. However, as it comes to the standard DZP basis
set, SCF convergence becomes difficult. I don't know what to do to improve it.
Here is my input file:
===========start of input.fdf================
SystemName 2Ni-2gra
SystemLabel 2Ni-2gra
NumberOfAtoms 6
Diag.ParallelOverK T
PAO.BasisSize DZ
NumberOfSpecies 2
%block ChemicalSpeciesLabel
1 28 Ni
2 6 C
%endblock ChemicalSpeciesLabel
LatticeConstant 2.48901587 Ang
%block LatticeVectors
0.866025404 -0.500000 0.00000000
0.866025404 0.500000 0.00000000
0.000000000 0.000000 12.05295650
%endblock LatticeVectors
%block kgrid_Monkhorst_Pack
6 0 0 0.0
0 6 0 0.0
0 0 1 0.0
%endblock kgrid_Monkhorst_Pack
SpinPolarized .false.
XC_functional GGA
XC_authors PBE
%block PS.lmax
C 2
%endblock PS.lmax
PAO.EnergyShift 50. meV
MeshCutoff 200. Ry
DM.UseSaveDM F
MaxSCFiterations 200
DM.MixingWeight 0.10
DM.NumberPulay 3
DM.Tolerance 0.0001
MD.NumCGsteps 100
MD.TypeOfRun CG
MD.UseSaveXV T
MD.UseSaveCG F
WriteMDXmol F
WriteForces T
SaveDeltaRho F
SaveRho F
%block GeometryConstraints
position from 1 to 1
%endblock GeometryConstraints
AtomicCoordinatesFormat Ang
%block AtomicCoordinatesAndAtomicSpecies
1.15470054 0.000 1.6256505400 1 #Ni
1.73205081 0.000 2.4336003900 1 #Ni
1.73205081 0.000 3.2861461800 2 #C
2.30940108 0.000 3.2861461800 2 #C
2.30940108 0.000 4.6320596600 2 #C
2.88675135 0.000 4.6320596600 2 #C
%endblock AtomicCoordinatesAndAtomicSpecies
===========end of input.fdf================
Here is part of my output file:
===========start of output.fdf================
.....
siesta: iscf Eharris(eV) E_KS(eV) FreeEng(eV) dDmax Ef(eV)
siesta: 1 -2512.1635 -2522.5031 -2522.5031 5.9203 -7.3552
timer: Routine,Calls,Time,% = IterSCF 1 133.954 82.97
elaps: Routine,Calls,Wall,% = IterSCF 1 11.239 82.68
siesta: 2 -2798.2370 -2503.2791 -2503.2853 15.2607 0.1093
siesta: 3 -2514.2022 -2519.9057 -2519.9121 6.0595 -7.7756
siesta: 4 -2513.5115 -2516.6410 -2516.6423 7.7241 -3.7334
siesta: 5 -2598.9529 -2517.6669 -2517.6798 5.9405 -1.3577
siesta: 6 -2541.5296 -2518.7682 -2518.7715 8.9084 -1.1456
siesta: 7 -2604.5084 -2510.6025 -2510.6047150.0320 -0.4481
siesta: 8 -3121.8587 -2483.1835 -2483.1859598.3458 1.7518
siesta: 9 -2977.9663 -2491.9150 -2491.9182596.9323 4.0476
siesta: 10 -3078.4553 -2498.1912 -2498.1984 62.3984 0.6857
siesta: 11 -4356.4281 -2361.6155 -2361.6199609.8885-39.3225
siesta: 12 -4489.7671 -2325.6771 -2325.6775599.9060-47.2102
siesta: 13 -4360.2034 -2338.9801 -2338.9801600.4145-43.2638
siesta: 14 -3448.0593 -2205.6430 -2205.6430 71.0008-56.8998
siesta: 15 -2579.5160 -2300.5191 -2300.5276 65.1504-24.0299
siesta: 16 -2525.8003 -2327.3343 -2327.3529 82.7621-16.0542
siesta: 17 -2555.9318 -2346.6249 -2346.6364 48.8877-15.5471
siesta: 18 -3513.9083 -2395.8520 -2395.8576 54.9869-12.0970
......
===========end of output.fdf================
Any suggestion is appreciated. Thanks alot!
Best wishes!
HHG
--
Magnetism and Magnetic Materials Division
Shenyang Materials Science National Laboratory
Institute of Metal Research
Chinese Academy of Sciences
72 Wenhua Road,Shenyang 110016, China
+86-15140243901 (mobile)
work: [email protected]
