Dear Michael!<div> To get an AFM ground state we I think we should have atleast two Mn atom. I did the calculation for Rocksalt symmetry but it was also not giving proper results.<br><br><div class="gmail_quote">
On Wed, Jan 19, 2011 at 11:52 PM, Mike Mehl <span dir="ltr"><<a href="mailto:Michael.Mehl@nrl.navy.mil">Michael.Mehl@nrl.navy.mil</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Two things:<br>
<br>
First,<br>
<br>
Having atoms designated Mn1 and Mn2 reduces the symmetry from Fm(3-)m<br>
(cubic rocksalt) to R(-3)m (rhombohedral), which is why you see a<br>
rhombohedral lattice in the output for the rocksalt structure.<br>
<br>
Second,<br>
<br>
What answer do you get when you use the primitive cell for the Rocksalt<br>
structure, rather than one that looks rhombohedral?<br>
<br>
CELL_PARAMETERS (cubic)<br>
0.0 0.5 0.5<br>
0.5 0.0 0.5<br>
0.5 0.5 0.0<br>
<br>
ATOMIC_POSITIONS (crystal)<br>
Se 0.00 0.00 0.00<br>
Mn 0.50 0.50 0.50<br>
<div><div></div><div class="h5"><br>
<br>
On 01/19/2011 11:57 AM, mohnish pandey wrote:<br>
> Dear QE users,<br>
> I am trying to do bulk calculations for MnSe<br>
> in rocksalt and wurtzite structure. Its has AFM ground state in rocksalt<br>
> structure but after checking convergence I am finding "rocksalt"<br>
> structure to be energetically higher than wurtzite structure. I am<br>
> pasting my segments of input and output files. Can anybody please help<br>
> me in figuring out the problem.<br>
><br>
> *INPUT FOR ROCKSALT*<br>
><br>
> &control<br>
> calculation = 'vc-relax'<br>
> restart_mode='restart',<br>
> wf_collect = .true.<br>
> prefix='mnse',<br>
> pseudo_dir = '/home/mohnish/mnse-rocksalt-bulk',<br>
> outdir='/home/mohnish/mnse-rocksalt-bulk',<br>
> tprnfor = .true.,<br>
> tstress=.true.<br>
> /<br>
> &system<br>
> ibrav= 0, celldm(1)= 10.3026, nat= 4, ntyp= 3,<br>
> ecutwfc = 40.0, ecutrho = 320.0,<br>
> occupations='smearing', smearing='gauss', degauss=0.01,<br>
> nspin=2,<br>
> starting_magnetization(1)= 0.0,<br>
> starting_magnetization(2)= 0.5,<br>
> starting_magnetization(3)=-0.5,<br>
> /<br>
> &electrons<br>
> diagonalization='david'<br>
> mixing_mode = 'plain'<br>
> mixing_beta = 0.4<br>
> conv_thr = 1.0d-8<br>
> startingpot = 'file'<br>
> startingwfc = 'file'<br>
> /<br>
> &IONS<br>
> ion_dynamics='bfgs'<br>
> trust_radius_max = 0.40<br>
> trust_radius_ini = 0.20<br>
> /<br>
> &CELL<br>
> cell_dynamics='bfgs',<br>
> /<br>
> ATOMIC_SPECIES<br>
> Se 78.960 Se.pbe-van.UPF<br>
> Mn1 54.938 Mn.pbe-sp-van_mit.UPF<br>
> Mn2 54.938 Mn.pbe-sp-van_mit.UPF<br>
> CELL_PARAMETERS<br>
> 0.50 0.50 1.00<br>
> 0.50 1.00 0.50<br>
> 1.00 0.50 0.50<br>
> ATOMIC_POSITIONS {crystal}<br>
> Se 0.25 0.25 0.25<br>
> Se 0.75 0.75 0.75<br>
> Mn1 0.0 0.0 0.0<br>
> Mn2 0.5 0.5 0.5<br>
> K_POINTS {automatic}<br>
> 6 6 6 0 0 0<br>
<br>
<br>
<br>
</div></div><font color="#888888">--<br>
Michael J. Mehl<br>
Head, Center for Computational Materials Science<br>
Naval Research Laboratory Code 6390<br>
Washington DC<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>Regards,<br>MOHNISH,<br>-----------------------------------------------------------------<br>Mohnish Pandey<br>Y6927262,5th Year dual degree student,<br>Department of Chemical Engineering,<br>
IIT KANPUR, UP, INDIA<br>-----------------------------------------------------------------<br>
</div>