[Wien] How to resolve the large charge fluctuation problem in heterojunction calculation

[Peter Blaha]

No wonder that you get convergence problems when you set EMIN in case.in1c
to -3.0 Ry  . Whith this setting you eventually cutoff the Ga-3d states.

Start over from scratch and do not change the defaults.

> Dear wien users,
> 
>         I am calculating a heterojunction of AlN/GaN. I find a large 
> charge fluctuation in the beginning of iteration and of course the ghost 
> band. This is the case.scf1 file, from which you can find the difference 
> of energy parameters of N atoms for the two sides of this superlattice 
> (1~6 for AlN, 7~12 for GaN) are very large. I have reduce the mxing parameter 
> to 0.0001, and still can not resolve this problem. Does any body can give me 
> some suggest?
> 
>           ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM  Ga1       
>           OVERALL ENERGY PARAMETER IS    0.3000
>           OVERALL BASIS SET ON ATOM IS LAPW
>           E( 2)=    0.7000   E(BOTTOM)=    0.570   E(TOP)=    0.830
>              APW+lo
>           E( 2)=    1.0000
>              LOCAL ORBITAL
>           E( 0)=    0.3000
>              APW+lo
>           E( 1)=    0.3000
>              APW+lo
> 
>           ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM  Ga2       
>           OVERALL ENERGY PARAMETER IS    0.3000
>           OVERALL BASIS SET ON ATOM IS LAPW
>           E( 2)=    2.0800   E(BOTTOM)=    2.080   E(TOP)= -200.000
>              APW+lo
>           E( 2)=    1.0000
>              LOCAL ORBITAL
>           E( 0)=    0.3000
>              APW+lo
>           E( 1)=    0.3000
>              APW+lo
> 
>           ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM  Ga3       
>           OVERALL ENERGY PARAMETER IS    0.3000
>           OVERALL BASIS SET ON ATOM IS LAPW
>           E( 2)=    2.6100   E(BOTTOM)=    2.610   E(TOP)= -200.000
>              APW+lo
>           E( 2)=    1.0000
>              LOCAL ORBITAL
>           E( 0)=    0.3000
>              APW+lo
>           E( 1)=    0.3000
>              APW+lo
> 
>           ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM  Ga4       
>           OVERALL ENERGY PARAMETER IS    0.3000
>           OVERALL BASIS SET ON ATOM IS LAPW
>           E( 2)=    2.3500   E(BOTTOM)=    2.350   E(TOP)= -200.000
>              APW+lo
>           E( 2)=    1.0000
>              LOCAL ORBITAL
>           E( 0)=    0.3000
>              APW+lo
>           E( 1)=    0.3000
>              APW+lo
> 
>           ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM  Ga5       
>           OVERALL ENERGY PARAMETER IS    0.3000
>           OVERALL BASIS SET ON ATOM IS LAPW
>           E( 2)=    1.6100   E(BOTTOM)=    1.610   E(TOP)= -200.000
>              APW+lo
>           E( 2)=    1.0000
>              LOCAL ORBITAL
>           E( 0)=    0.3000
>              APW+lo
>           E( 1)=    0.3000
>              APW+lo
> 
>           ATOMIC SPHERE DEPENDENT PARAMETERS FOR ATOM  Ga6       
>           OVERALL ENERGY PARAMETER IS    0.3000
>           OVERALL BASIS SET ON ATOM IS LAPW
>           E( 2)=    0.3400   E(BOTTOM)=    0.210   E(TOP)=    0.470
>              APW+lo
>           E( 2)=    1.0000
>              LOCAL ORBITAL
>           E( 0)=    0.3000
>              APW+lo
>           E( 1)=    0.3000
>              APW+lo
> 
>        K=   0.06250   0.06250   0.50000            1
> :RKM  : MATRIX SIZE 3918LOs: 168  RKM= 7.00  WEIGHT= 4.00  PGR:    
>        EIGENVALUES ARE:
>         -2.9833287   -2.9033434   -2.8711489   -2.8623625   -2.7906554
>         -2.7762807   -2.7674714   -2.5528370   -2.4163669   -2.3959290
>         -2.3743166   -2.3030169   -2.2624883   -1.9394406   -1.9244714
>         -1.8911925   -1.8833915   -1.8101535   -1.7608643   -1.7470634
>         -1.7139419   -1.6932904   -1.5676893   -1.5377474   -1.5116763
>         -1.5052158   -1.4501798   -1.4001378   -1.3946959   -1.3802247
>         -1.3524068   -1.3043611   -1.2374109   -1.1504261   -1.1233582
>         -1.0930868   -1.0755032   -1.0642763   -1.0264128   -0.9528169

>            11 EIGENVALUES BELOW THE ENERGY   -3.00000
>        ********************************************************
> 
>            11 EIGENVALUES BELOW THE ENERGY   -3.00000
>        NUMBER OF K-POINTS:            16
>    
>  
> 
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> 


                                      P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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