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<p>Dear All,</p>
<p><br>
</p>
<p>I have tried the following changes to the system (see latest input file below), all of which still converge to the non-magnetic state regardless of starting magnetization:</p>
<p><br>
</p>
<p></p>
<ol style="margin-bottom:0px; margin-top:0px">
<li><span style="font-size:12pt"></span>Breaking the symmetry by treating the two O atoms as different species (the unit cell contains 1 Mn and 2 O)</li><li>Introducing the nbnd parameter into &system</li><li>Running the simulation with a finer k-mesh (21x21x7)</li><li>With and without the Hubbard correction</li><li>With and without using noncolin=.true.</li><li>And alternative pseudopotentials (namely <span>Mn.pbe-spn-rrkjus_psl.0.3.1.UPF and <span>O.pbe-rrkjus.upf.UPF)</span></span></li></ol>
<div>Some papers mention that the ferromagnetism was observed, and others don't mention it at all.</div>
<div><br>
</div>
<div>I have approached the other members of my group as well to no avail. I have been stuck with this for a month <span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols; font-size:16px">and
would truly appreciate any advice or other suggestions </span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols; font-size:16px">you may have</span><span style="font-family:Calibri,Helvetica,sans-serif,EmojiFont,"Apple Color Emoji","Segoe UI Emoji",NotoColorEmoji,"Segoe UI Symbol","Android Emoji",EmojiSymbols; font-size:16px">.</span></div>
<div><br>
</div>
<div>
<div>&control</div>
<div> disk_io = 'high',</div>
<div> calculation ='vc-relax',</div>
<div> restart_mode = 'from_scratch'</div>
<div> prefix = 'all',</div>
<div> outdir = './all',</div>
<div> Pseudo_dir = './'</div>
<div> nstep=250,</div>
<div>/</div>
<div><br>
</div>
<div>&system</div>
<div> lda_plus_u=.true.</div>
<div> hubbard_U(1)= 3.9</div>
<div> degauss = 1.00000e-02</div>
<div> ecutrho = 2.25000e+02</div>
<div> ecutwfc = 2.50000e+01</div>
<div> ibrav = 0</div>
<div> nat = 3</div>
<div> nspin = 2</div>
<div> ntyp = 3</div>
<div> occupations = "smearing"</div>
<div> smearing = "gaussian"</div>
<div> starting_magnetization(1) = 1.00000</div>
<div> starting_magnetization(2) = -0.60000e+00</div>
<div> starting_magnetization(3) = -0.60000e+00</div>
<div> nbnd = 19</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div> /</div>
<div><br>
</div>
<div> &electrons</div>
<div> conv_thr = 1.00000e-06</div>
<div> electron_maxstep = 200</div>
<div> mixing_beta = 4.00000e-01</div>
<div> startingpot = "atomic"</div>
<div> startingwfc = "atomic+random"</div>
<div><br>
</div>
<div>/</div>
<div><br>
</div>
<div> &ions</div>
<div> ion_dynamics = 'bfgs'</div>
<div> /</div>
<div><br>
</div>
<div> &cell</div>
<div> cell_factor=6.0,</div>
<div> cell_dofree = '2Dxy',</div>
<div> /</div>
<div><br>
</div>
<div><br>
</div>
<div>CELL_PARAMETERS {angstrom}</div>
<div><br>
</div>
<div> 2.240463696 -0.000000000 0.000000000</div>
<div> -1.120231848 1.940298414 0.000000000</div>
<div> 0.000000000 0.000000000 17.431921826</div>
<div><br>
</div>
<div>ATOMIC_SPECIES</div>
<div><br>
</div>
<div> Mn 54.9380 Mn.pbe-spn-rrkjus_psl.0.3.1.UPF</div>
<div> O1 15.9994 O.pbe-n-kjpaw_psl.0.1.upf</div>
<div> O2 15.9994 O.pbe-n-kjpaw_psl.0.1.upf</div>
<div><br>
</div>
<div>ATOMIC_POSITIONS {angstrom}</div>
<div><br>
</div>
<div>Mn 0.000000000 0.000000000 0.603503436</div>
<div>O1 1.120233376 0.646765629 -0.789807394</div>
<div>O2 -0.000000765 1.293533550 1.997300505</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div>K_POINTS automatic</div>
<div>21 21 7 1 1 1</div>
<div><br>
</div>
<br>
</div>
<div><br>
</div>
<div>Thanks so much,</div>
<div><br>
</div>
<div>Lance Kavalsky</div>
<div>MASc student</div>
<div>Dept. of Materials Science and Engineering</div>
<div>University of Toronto</div>
<p></p>
</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> pw_forum-bounces@pwscf.org <pw_forum-bounces@pwscf.org> on behalf of Lorenzo Paulatto <lorenzo.paulatto@impmc.upmc.fr><br>
<b>Sent:</b> Thursday, September 7, 2017 3:39:53 AM<br>
<b>To:</b> pw_forum@pwscf.org<br>
<b>Subject:</b> Re: [Pw_forum] Problems Computing Cholesky for VC-Relax of MnO2</font>
<div> </div>
</div>
</div>
<font size="2"><span style="font-size:10pt;">
<div class="PlainText">On 06/09/17 21:01, Lance Kavalsky wrote:<br>
> I am no longer getting the error after increasing the energy cutoff of <br>
> the wavefunctions to 250.0 Ry, decreasing the smearing to 0.01, and <br>
> resetting the diagonalization back to davidson.<br>
<br>
<br>
You mean of the charge density cutoff?<br>
<br>
> I have experimented with varying the starting magnetizations and it <br>
> consistently converges to a non-magnetic state. However, M. Kan et al. <br>
> showed that a ferromagnetic state should exist via DFT (J. Phys. Chem. <br>
> Lett., *2013*, /4/ (20), pp 3382–3386). Is this lack of magnetic states <br>
> in my investigations more likely a result of not yet discovering a <br>
> suitable starting magnetization, or could there be another reason such <br>
> as choice of pseudopotentials?<br>
> <br>
I do not know your system, but you may have to start with to different <br>
species of Mg, in order to break symmetry. This is necessary if one of <br>
the symmetries of your crystal send Mg1 to Mg2 changing its orientation.<br>
<br>
Example:<br>
<br>
nat=4, ntyp=3,<br>
...<br>
starting_magnetization(1)=0.5 !Mn1<br>
starting_magnetization(2)=0.5 !Mn2<br>
starting_magnetization(3)=-0.5 !Oxygen<br>
...<br>
ATOMIC_SPECIES<br>
Mn1 54.9380 Mn.pbe-spn-kjpaw_psl.0.3.1.upf<br>
Mn2 54.9380 Mn.pbe-spn-kjpaw_psl.0.3.1.upf<br>
O 15.9994 O.pbe-n-kjpaw_psl.0.1.upf<br>
<br>
ATOMIC_POSITIONS {angstrom}<br>
Mn1 1.463698094 2.529784343 0.000006382<br>
Mn2 2.923484801 0.001355102 1.898036230<br>
O 0.003938199 1.686984261 0.949009435<br>
O 1.463753969 0.844151693 2.847056902<br>
<br>
<br>
[resending to list]<br>
<br>
-- <br>
Dr. Lorenzo Paulatto<br>
IdR @ IMPMC -- CNRS & Université Paris 6<br>
phone: +33 (0)1 442 79822 / skype: paulatz<br>
www: <a href="http://www-int.impmc.upmc.fr/~paulatto/">http://www-int.impmc.upmc.fr/~paulatto/</a><br>
mail: 23-24/423 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05<br>
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