<div dir="ltr"><div><div>Hi,<br><br></div>If you want to compare the band structures of two different supercells, I think you can consider the high symmetry points of the respective lattice systems, as usual. If your slab is orthorhombic, a path<br><br>gamma X U Z gamma U R Y gamma<br><br></div><div>should be enough. See also<br></div><br><a href="https://en.wikipedia.org/wiki/Brillouin_zone#Orthorhombic_lattice_system_ORC.281.29.2C_ORCC.281.29.2C_ORCI.281.29.2C_ORCF.283.29" target="_blank">https://en.wikipedia.org/wiki/<wbr>Brillouin_zone#Orthorhombic_la<wbr>ttice_system_ORC.281.29.2C_ORC<wbr>C.281.29.2C_ORCI.281.29.2C_ORC<wbr>F.283.29</a><br><div><br></div><div>Now, if your intention is discuss some localized electronic states over the surface, I think that a projected density of states would be more appropriated. It is not clear to me what you meant by "slab geometry", but momentum is not precisely defined for small regions in the real space of your system.<br><br><span class="m_-6321344893763153737m_6333377370348176066gmail-m_-7443609597193345283gmail-m_-4627483426385706070m_-3659475676208332197gmail-m_318366166282958700m_-4069557267744183932m_3925019048408858411m_5074883181905464774gmail-il">Ary Ferreira<br></span><span class="m_-6321344893763153737m_6333377370348176066gmail-m_-7443609597193345283gmail-m_-4627483426385706070m_-3659475676208332197gmail-m_318366166282958700m_-4069557267744183932m_3925019048408858411m_5074883181905464774gmail-il"><br><span class="m_-6321344893763153737m_6333377370348176066gmail-m_-7443609597193345283gmail-il">FAPESP</span> </span><span class="m_-6321344893763153737m_6333377370348176066gmail-m_-7443609597193345283gmail-m_-4627483426385706070m_-3659475676208332197gmail-m_318366166282958700m_-4069557267744183932m_3925019048408858411m_5074883181905464774gmail-il">postdoctoral</span> fellow<br><span class="m_-6321344893763153737m_6333377370348176066gmail-il">UFSCar</span> - Brazil</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Apr 29, 2017 at 4:43 AM, Christoph Wolf(신소재공학과) <span dir="ltr"><<a href="mailto:chwolf@postech.ac.kr" target="_blank">chwolf@postech.ac.kr</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div link="#0563C1" vlink="#954F72" lang="EN-US">
<div class="m_3256781416179530060WordSection1">
<p class="MsoNormal">Dear all!<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I have come across an impasse and I am hoping for some stimulating input…<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I work on CsPbBr3 (cubic unit cell, a=5.6 A). I construct a vacuum (5L)-slab (7L)-vacuum (5L) (L=layer numbers in multiple of the lattice constant in z-direction) symmetric slab (exposing the 100 CsBr terminated surface) and calculate
the SCF/NSCF after a relax run. During relaxing the surface layer moves slightly “into the vacuum”, by ~5% (d12) and the next layer moves slightly inwards by ~2% (d23). Pp.x gives nice electron density surfaces and potentials (plot_num=0,11);<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Now I wanted to plot the band-structure to investigate the influence of slab geometry on the band-structure but I am (shameful!) not sure how to define the k-path in order to get a “surface” band-structure. Frankly speaking, I am not entirely
sure that would be even physically meaningful, but I have seen similar calculations for other slab geometries (e.g.
<a href="https://arxiv.org/pdf/1609.09262.pdf" target="_blank">https://arxiv.org/pdf/1609.<wbr>09262.pdf</a>).<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I attached the input file to the nscf calculation (i.e. after the relax run) to illustrate the geometry, any help is greatly appreciated!<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Yours,<u></u><u></u></p>
<p class="MsoNormal">Chris<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">Postech University<u></u><u></u></p>
<p class="MsoNormal">Materials Science and Engineering<u></u><u></u></p>
<p class="MsoNormal">Pohang, ROK <u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
</div>
<br>______________________________<wbr>_________________<br>
Pw_forum mailing list<br>
<a href="mailto:Pw_forum@pwscf.org">Pw_forum@pwscf.org</a><br>
<a href="http://pwscf.org/mailman/listinfo/pw_forum" rel="noreferrer" target="_blank">http://pwscf.org/mailman/<wbr>listinfo/pw_forum</a><br></blockquote></div><br><br clear="all"><br>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><a href="http://lattes.cnpq.br/8221674673413336" target="_blank">http://lattes.cnpq.br/8221674673413336</a></div>
</div>