<div dir="ltr"><div><div><div>thank you Dario. When I use VASP I get the exact same result as mentioned in the reference you have atatched but with quantum espresso I get significantly different result especially the band gap. <br></div>If you can have a look at the relax input file I have attached in the email and let met know if I should add anything else ?<br><br> <br>&CONTROL
<br> calculation='vc-relax',
<br> outdir='./',
<br> prefix='calc',
<br> pseudo_dir='./',
<br> verbosity='high',
<br>/
<br> <br>&SYSTEM
<br> ibrav=0,
<br> celldm(1)= 8.276999830d0
<br> nat=4,
<br> ntyp=1,
<br> ecutwfc=60,
<br> ecutrho=360,
<br> input_dft='lda',
<br> occupations='smearing',
<br> smearing='mv',
<br> degauss=0.005d0,
<br>/
<br> <br>&ELECTRONS
<br> conv_thr=1d-06,
<br> mixing_beta=0.7d0,
<br>/
<br>&IONS
<br> ion_dynamics='bfgs'
<br>/
<br> <br>&CELL
<br> cell_dynamics='bfgs'
<br> cell_dofree='2Dshape'
<br>/
<br>ATOMIC_SPECIES
<br> P 30.973800d0 P.pw-mt_fhi.UPF
<br> <br>ATOMIC_POSITIONS {crystal}
<br> <br> P 0.090000004 0.000000000 0.050195117
<br> P 0.909999967 0.000000000 0.949804902
<br> P 0.590000033 0.500000000 0.949804902
<br> P 0.409999996 0.500000000 0.050195117
<br> <br>K_POINTS {automatic}
<br> <br> 12 12 1 0 0 0
<br> <br>CELL_PARAMETERS {alat}
<br> <br> 1.0000000000000000 0.0000000000000000 0.0000000000000000
<br> 0.0000000000000000 0.7511415530000000 0.0000000000000000
<br> 0.0000000000000000 0.0000000000000000 4.68036529200000000<br><br></div>thank you<br></div>Gautam<br><div><div><div><br></div></div></div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">GAUTAM GADDEMANE<div>DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING</div><div>UNIVERSITY OF TEXAS AT DALLAS</div></div></div></div>
<br><div class="gmail_quote">On Thu, Oct 5, 2017 at 3:54 PM, dario rocca <span dir="ltr"><<a href="mailto:roccad@gmail.com" target="_blank">roccad@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear Gautam,<div>The values you get are not completely impossible.<br><div>Try with PBE, since there are for sure a couple of calculations in the literature to compare with.</div></div><div>For example</div><div><a href="https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.085402" target="_blank">https://journals.aps.org/prb/<wbr>abstract/10.1103/PhysRevB.90.<wbr>085402</a><br></div><div>Best,</div><div>Dario</div></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Oct 5, 2017 at 10:31 PM, Gautam Gaddemane <span dir="ltr"><<a href="mailto:gautamg88@gmail.com" target="_blank">gautamg88@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">4.45 A and 3.26 A and a band gap of 0.67eV.</div><div class="gmail_extra"><span><br clear="all"><div><div class="m_425397436961710348m_6787477276787962591gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">GAUTAM GADDEMANE<div>DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING</div><div>UNIVERSITY OF TEXAS AT DALLAS</div></div></div></div>
<br></span><div><div class="m_425397436961710348h5"><div class="gmail_quote">On Thu, Oct 5, 2017 at 3:28 PM, Matthieu Fortin-Deschênes <span dir="ltr"><<a href="mailto:matthieu.fortin-deschenes@polymtl.ca" target="_blank">matthieu.fortin-deschenes@pol<wbr>ymtl.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">What values of lattice parameters and band gap did you get? With LDA<br>
you expect some differences compared to experimental values.<br>
<br>
Matthieu<br>
<br>
Gautam Gaddemane <<a href="mailto:gautamg88@gmail.com" target="_blank">gautamg88@gmail.com</a>> a écrit :<br>
<div><div class="m_425397436961710348m_6787477276787962591h5"><br>
> Dear All,<br>
><br>
> I am trying to calculate the bands tructure for monolayer phosphorene and I<br>
> am just a week old in using quantum espresso.<br>
>> From the bulk unit cell I prepared an input file to relax the structure but<br>
> I was not able to get a good lattice constant nor a good band gap. It would<br>
> be very helpful if someone would guide me in this procedure.<br>
> I have attahced the file I used to relax in this email<br>
><br>
><br>
> &CONTROL<br>
> calculation='vc-relax',<br>
> outdir='./',<br>
> prefix='calc',<br>
> pseudo_dir='./',<br>
> verbosity='high',<br>
> /<br>
><br>
> &SYSTEM<br>
> ibrav=0,<br>
> celldm(1)= 8.276999830d0<br>
> nat=4,<br>
> ntyp=1,<br>
> ecutwfc=60,<br>
> ecutrho=360,<br>
> input_dft='lda',<br>
> occupations='smearing',<br>
> smearing='mv',<br>
> degauss=0.005d0,<br>
> /<br>
><br>
> &ELECTRONS<br>
> conv_thr=1d-06,<br>
> mixing_beta=0.7d0,<br>
> /<br>
> &IONS<br>
> ion_dynamics='bfgs'<br>
> /<br>
><br>
> &CELL<br>
> cell_dynamics='bfgs'<br>
> cell_dofree='2Dshape'<br>
> /<br>
> ATOMIC_SPECIES<br>
> P 30.973800d0 P.pw-mt_fhi.UPF<br>
><br>
> ATOMIC_POSITIONS {crystal}<br>
><br>
> P 0.090000004 0.000000000 0.050195117<br>
> P 0.909999967 0.000000000 0.949804902<br>
> P 0.590000033 0.500000000 0.949804902<br>
> P 0.409999996 0.500000000 0.050195117<br>
><br>
> K_POINTS {automatic}<br>
><br>
> 12 12 1 0 0 0<br>
><br>
> CELL_PARAMETERS {alat}<br>
><br>
> 1.0000000000000000 0.0000000000000000 0.0000000000000000<br>
> 0.0000000000000000 0.7511415530000000 0.0000000000000000<br>
> 0.0000000000000000 0.0000000000000000 4.68036529200000000<br>
><br>
><br>
> thank you<br>
> Gautam<br>
><br>
> GAUTAM GADDEMANE<br>
> DEPARTMENT OF MATERIALS SCIENCE AND ENGINEERING<br>
> UNIVERSITY OF TEXAS AT DALLAS<br>
<br>
<br>
<br>
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