[Pw_forum] Convergence of LaCoO3

[stefano de gironcoli]

dear Amita Sihag

is it reasonable that La-O and Sr-O distances are only slightly above 1 AA ?
is it reasonable to assume starting magnetization on all atoms including 
O and Pt ?
is it reasonable to use occupation fixed in this non collinear magnetic 
system ?
how important is non-collinearity in the system ?
I would start by optimizing the system in the collinear case, even 
starting with the undoped case to see where it wants to go and add 
complications one at at time..
HTH
stefano
PS: i would not insist beyond a few tens of electronic iteration, let's 
say 100 if the system is magnetic... If it does not converge this means 
there is something wrong in the system.

On 10/10/2016 09:31, Amita Sihag wrote:
>
> &CONTROL
>                        title = 'LaCoO3' ,
>                       prefix = 'LaCoO3'
>                  calculation = 'vc-relax' ,
>                  max_seconds = 1.0d+7 ,
>                   wf_collect = .TRUE. ,
>                 restart_mode = 'restart'
>                       outdir = 
> '/home/SSM_grp/amitasihag/LaCoO3/221/doping/SrPt_mag/out' ,
>                   pseudo_dir = './' ,
> /
> &SYSTEM
>                        ibrav = 0,
>                     celldm(1)= 1.89 ,
>                          nat = 40,
>                         ntyp = 5 ,
>                     noncolin = .true. ,
>    starting_magnetization(1) = 1.5 ,
>    starting_magnetization(2) = 1.5 ,
>    starting_magnetization(3) = 1.0 ,
>    starting_magnetization(4) = 1.5 ,
>    starting_magnetization(5) = 1.5 ,
>                      ecutwfc = 30 ,
>                      ecutrho = 300 ,
>                  occupations = 'fixed'
> /
> &ELECTRONS
>             electron_maxstep = 1500 ,
>                     conv_thr = 1.0d-4 ,
>                  mixing_mode = 'plain' ,
>                  mixing_beta = 0.2 ,
>              diagonalization = 'david' ,
>
> /
> &IONS
> /
> &CELL
> /
> CELL_PARAMETERS alat
>    10.7399997711   0.0000000000   0.0000000000
>     5.2412480519   9.3742687151   0.0000000000
>     2.6206240259   1.5372037335   4.4278926328
>
> ATOMIC_SPECIES
>    Sr   87.62  Sr.pbe-nsp-van.UPF
>    Pt   195.08 Pt.pbe-n-van.UPF
>    La   138.91 La.pbe-nsp-van.UPF
>    Co   58.933 Co.pbe-sp-van.UPF
>    O    15.999 O.pbe-van_ak.UPF
>
> ATOMIC_POSITIONS alat
> Sr   2.652812105   1.556084500   1.106973092
> Pt   7.990623911   4.687134358   0.000000000
> La   5.273436131   6.243218857   1.106973092
> La   8.022811831   1.556084500   1.106973092
> La  10.643435857   6.243218857   1.106973092
> La   7.958435953   4.668253568   3.320919475
> La  10.579059979   9.355387926   3.320919475
> La  13.328435839   4.668253568   3.320919475
> La  15.949059865   9.355387926   3.320919475
> Co   0.000000000   0.000000000   0.000000000
> Co   2.620624026   4.687134358   0.000000000
> Co   5.369999886   0.000000000   0.000000000
> Co   5.305624211   3.112169000   2.213946184
> Co   7.926248237   7.799303357   2.213946184
> Co  10.675623776   3.112169000   2.213946184
> Co  13.296247802   7.799303357   2.213946184
> O    7.414334322   5.595837165   3.320919475
> O   10.034958348  10.282971523   3.320919475
> O   12.784333887   5.595837165   3.320919475
> O   15.404957913  10.282971523   3.320919475
> O    3.196913420   0.628500623   1.106973092
> O    5.817537290   5.315634702   1.106973092
> O    8.566913626   0.628500623   1.106973092
> O   11.187537496   5.315634702   1.106973092
> O    7.958435953   4.044882307   4.197199414
> O   10.579059823   8.732016385   4.197199414
> O   13.328435839   4.044882307   4.197199414
> O   15.949059708   8.732016385   4.197199414
> O    2.652812135   2.179455779   0.230693202
> O    5.273436317   6.866590416   0.230693202
> O    8.022811860   2.179455779   0.230693202
> O   10.643436042   6.866590416   0.230693202
> O    8.502537428   4.364040954   2.444639535
> O   11.123161454   9.051175311   2.444639535
> O   13.872537634   4.364040954   2.444639535
> O   16.493161660   9.051175311   2.444639535
> O    2.108710530   1.860297068   1.983253098
> O    4.729334595   6.547431495   1.983253098
> O    7.478710676   1.860297068   1.983253098
> O   10.099334741   6.547431495   1.983253098
>
> K_POINTS automatic
> 2 2 4  0 0 0