[Pw_forum] a question about MnSe

[Duy Le]

Did you check the k-mesh? Are 6 6 6 and 6 6 4 good for converged energy?
--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.

"Men don't need hand to do things"



On Wed, Jan 19, 2011 at 11:57 AM, mohnish pandey <mohnish.iitk at gmail.com> wrote:
> Dear QE users,
>                            I am trying to do bulk calculations for MnSe in
> rocksalt and wurtzite structure. Its has AFM ground state in rocksalt
> structure but after checking convergence I am finding "rocksalt" structure
> to be energetically higher than wurtzite structure. I am pasting my segments
> of input and output files. Can anybody please help me in figuring out the
> problem.
> INPUT FOR ROCKSALT
> &control
>     calculation = 'vc-relax'
>     restart_mode='restart',
>     wf_collect = .true.
>     prefix='mnse',
>     pseudo_dir = '/home/mohnish/mnse-rocksalt-bulk',
>     outdir='/home/mohnish/mnse-rocksalt-bulk',
>     tprnfor = .true.,
>     tstress=.true.
>  /
>  &system
>     ibrav=  0, celldm(1)= 10.3026, nat=  4, ntyp= 3,
>     ecutwfc = 40.0, ecutrho = 320.0,
>     occupations='smearing', smearing='gauss', degauss=0.01,
>     nspin=2,
>     starting_magnetization(1)= 0.0,
>     starting_magnetization(2)= 0.5,
>     starting_magnetization(3)=-0.5,
>  /
>  &electrons
>    diagonalization='david'
>    mixing_mode = 'plain'
>    mixing_beta = 0.4
>    conv_thr = 1.0d-8
>    startingpot = 'file'
>    startingwfc = 'file'
>  /
> &IONS
>   ion_dynamics='bfgs'
>   trust_radius_max = 0.40
>   trust_radius_ini = 0.20
> /
> &CELL
>   cell_dynamics='bfgs',
> /
> ATOMIC_SPECIES
>   Se  78.960 Se.pbe-van.UPF
>   Mn1 54.938 Mn.pbe-sp-van_mit.UPF
>   Mn2 54.938 Mn.pbe-sp-van_mit.UPF
> CELL_PARAMETERS
> 0.50 0.50 1.00
> 0.50 1.00 0.50
> 1.00 0.50 0.50
> ATOMIC_POSITIONS {crystal}
>  Se  0.25 0.25 0.25
>  Se  0.75 0.75 0.75
>  Mn1 0.0  0.0  0.0
>  Mn2 0.5  0.5  0.5
> K_POINTS {automatic}
> 6 6 6 0 0 0
> OUTPUT FOR ROCKSALT
>  bfgs converged in   8 scf cycles and   4 bfgs steps
>      (criteria: energy < 0.10E-03, force < 0.10E-02, cell < 0.50E+00)
>      End of BFGS Geometry Optimization
>      Final enthalpy =    -464.4688263706 Ry
> Begin final coordinates
>      new unit-cell volume =    533.55466 a.u.^3 (    79.06464 Ang^3 )
> CELL_PARAMETERS (alat= 10.30260000)
>    0.494008772   0.494008772   0.990589056
>    0.494008772   0.990589056   0.494008772
>    0.990589056   0.494008772   0.494008772
> ATOMIC_POSITIONS (crystal)
> Se       0.249999854   0.249999854   0.249999854
> Se       0.750000146   0.750000146   0.750000146
> Mn1      0.000000000   0.000000000   0.000000000
> Mn2      0.500000000   0.500000000   0.500000000
> End final coordinates
> INPUT FOR WURTZITE
> &control
>     calculation = 'vc-relax',
>     restart_mode='restart',
>     verbosity = 'high'
>     wf_collect = .true.
>     outdir='/home/mohnish/mnse-wurtzite-bulk',
>     pseudo_dir='/home/mohnish/mnse-wurtzite-bulk'
>     prefix='mnse',
>     tstress = .true.,
>     tprnfor = .true.,
> /
>  &system
>     ibrav=  4, a = 4.178, c = 6.783,nat= 4, ntyp= 3,
>     ecutwfc =
> 40,ecutrho=320,occupations='smearing',degauss=0.01,smearing='gaussian',
>     nspin =2,starting_magnetization(1)=0.5,starting_magnetization(2)= -0.5,
> /
>  &electrons
>    diagonalization='david'
>    mixing_mode = 'plain'
>    mixing_beta = 0.4
>    conv_thr = 1.0d-8
>    startingpot = 'file'
>    startingwfc = 'file'
>  /
> &IONS
>   ion_dynamics='bfgs'
>   trust_radius_max = 0.40
>   trust_radius_ini = 0.20
> /
> &CELL
>   cell_dynamics='bfgs',
> /
> ATOMIC_SPECIES
>   Mn1 54.938 Mn.pbe-sp-van_mit.UPF
>   Mn2 54.938 Mn.pbe-sp-van_mit.UPF
>   Se  78.960 Se.pbe-van.UPF
> ATOMIC_POSITIONS (crystal)
>   Mn1  0.000000000  0.000000000000  0.000000000
>   Mn2  0.333333333  0.666666666667  0.500000000
>   Se   0.000000000  0.000000000000  0.345000000
>   Se   0.333333333  0.666666666667  0.845000000
>  K_POINTS (automatic)
>  6 6 4 0 0 0
> OUTPUT FOR WURTZITE
>  End of BFGS Geometry Optimization
>      Final enthalpy =    -464.4799667612 Ry
> Begin final coordinates
>      new unit-cell volume =    681.36082 a.u.^3 (   100.96726 Ang^3 )
> CELL_PARAMETERS (alat=  7.89527578)
>    1.001414763   0.000000000   0.000000000
>   -0.500707382   0.867250625   0.000000000
>    0.000000000   0.000000000   1.594103933
> ATOMIC_POSITIONS (crystal)
> Mn1      0.000000000   0.000000000  -0.014999731
> Mn2      0.333333333   0.666666667   0.485592670
> Se       0.000000000   0.000000000   0.359333481
> Se       0.333333333   0.666666667   0.860073579
> End final coordinates
>
>
>
>
> --
> Regards,
> MOHNISH,
> -----------------------------------------------------------------
> Mohnish Pandey
> Y6927262,5th Year dual degree student,
> Department of Chemical Engineering,
> IIT KANPUR, UP, INDIA
> -----------------------------------------------------------------
>
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