<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">Hi QE users,</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">I am trying to do some calculations for bulk PbSe, which is simple rocksalt structure with 2 atoms in the unit cell.</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">The pseudo I am using are as follows:</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">Pb.pz-dn-rrkjus_psl.0.2.2.UPF</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">Se.pz-n-rrkjus_psl.0.2.UPF</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">However, these PP can not generate the correct phonon dispersion and the TO-LO splitting at Gamma point is also </span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">considerably underestimated. Experimental data is around 85cm-1, while I am getting 12cm-1.</span><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<br></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">I understand that this may due to the effect Spin-Orbital Coupling is not included in the calculation, since I am using non-relativistic PPs.<br>
<br>Recently published papers have mentioned that they are using "Pb.rel-pz-nc.UPF" and "Se.rel-pz-nc.UPF" files<br>from PSlibrary for bulk PbSe phonon calculations.<br><br>However, I checked the PSlibrary0.2.5 patch and could not find "Pb.rel-pz-nc.UPF" and "Se.rel-pz-nc.UPF" files.<br>
<br>I am wondering whether any of you happen to have those PP files, if so could you please send them to me?<br><br>Any suggestion on how to improve the phonon dispersion is also appreciated!<br><br>Thank you,<br>Rui Mao<br>
<br>My input files:<br><br><b>SCF.in:</b><br><br>&control<br> calculation = 'scf',<br> restart_mode='from_scratch',<br> wf_collect = .true.,<br> prefix='PbSe',<br> tstress = .true.<br>
tprnfor = .true.<br> forc_conv_thr = 1.0D-3,<br> etot_conv_thr = 1.0D-4,<br> pseudo_dir = 'xxx',<br> outdir='xxx',<br> /<br> &system<br> ibrav=2, celldm(1) =11.4236, nat=2, ntyp= 2,<br>
! lspinorb=.true.,<br> ! noncolin=.true.,<br> ecutwfc =50,<br> ecutrho=700,<br> ! occupations='smearing', smearing='mp', degauss=0.01,<br> /<br> &electrons<br> diagonalization='david',<br>
mixing_mode = 'plain',<br> mixing_beta = 0.5,<br> conv_thr = 1.0d-8,<br>/<br>ATOMIC_SPECIES<br>Pb 207.2 Pb.pz-dn-rrkjus_psl.0.2.2.UPF<br>Se 78.96 Se.pz-n-rrkjus_psl.0.2.UPF<br>ATOMIC_POSITIONS {crystal}<br>
Pb 0.000000000 0.000000000 0.000000000<br>Se 0.500000000 0.500000000 0.500000000 <br>K_POINTS {automatic}<br>10 10 10 0 0 0<br><br><b>PH.in:</b><br><br><div>phonons of PbSe_bulk</div><div> &inputph</div>
<div> tr2_ph=1.0d-16,</div><div> alpha_mix(1)=0.5,</div><div> prefix='PbSe',</div><div> ldisp=.true.,</div><div> epsil=.true.,</div><div> recover=.false.,</div><div> reduce_io=.true.,</div><div> amass(1)=207.2,</div>
<div> amass(2)=78.96,</div><div> nq1=6, nq2=6, nq3=6,</div><div> outdir='XXX',</div><div> fildyn='PbSe.dyn'</div><div> /</div></div><div><br></div>-- <br>Rui Mao<br>============================================================<br>
Department of Electrical and Computer Engineering (ECE)<br>North Carolina State University (NCSU)<br>Raleigh, NC, 27606<br>Email: <a href="mailto:ruimao20@gmail.com" target="_blank">ruimao20@gmail.com</a><br>============================================================<br>