<div dir="ltr"><div>Hi,</div><div><br></div>the OP might need to be a bit careful with the definition of the fermi energy and explain what they are after. I think there are different conventions around.<div><br></div><div>I think the free-electron models he referred to, and that 7 eV for copper number, measure the chemical potential / fermi energy relative to the bottom of the band. So it corresponds to something like the energy from the lowest 4s copper states up to the highest occupied states. What you would use it for, I am not quite sure.</div><div><br></div><div>So I think it is not the same thing as a physical measure relative to the vacuum, i.e. work function.</div><div><br></div><div>Matt<br><br>On Wednesday, February 8, 2017 at 10:15:19 PM UTC, Ari Paavo Seitsonen wrote:<blockquote class="gmail_quote" style="margin: 0;margin-left: 0.8ex;border-left: 1px #ccc solid;padding-left: 1ex;"><div dir="ltr"><div><div><div>Dear A<span title="ashish dabral">shish Dabral,<br><br></span></div><span title="ashish dabral"> The only way _I_ know is to calculate a system with surface (well, two, slab model) and then align the Fermi energy via the potential in the middle of the slab - should be thick enough so that in the middle it is converged - and the potential in the middle of the vacuum. So the value of "Fermi energy" would be the work function. I guess that one would get the same value if one would then take the difference of the potential in the middle of the slab and potential in the vacuum, and then uses that after aliging the difference between the potential and the Fermi energy in a bulk system.<br><br></span></div><div><span title="ashish dabral"> With GGA one usually gets too small values of the work function if I remember correctly (self-interaction/asymptotics)<wbr>, by about 0.5-1 eV depending on the material.<br></span></div><div><span title="ashish dabral"><br></span></div><span title="ashish dabral"> Greetings,<br><br></span></div><span title="ashish dabral"> apsi<br></span></div><div><br><div class="gmail_quote">2017-02-08 17:17 GMT+01:00 ashish dabral <span dir="ltr"><<a href="javascript:" target="_blank" gdf-obfuscated-mailto="wK4CyCAsBgAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">ashis...@gmail.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Hi, <div><br></div><div>I would like to know how to calculate the fermi energy of metals using cp2k. </div><div>For example, Cu has a fermi energy of around 7.0eV, which can also be </div><div>calculated using the general formula involving carrier concentration (<a href="https://en.wikipedia.org/wiki/Fermi_energy" target="_blank" rel="nofollow" onmousedown="this.href='https://www.google.com/url?q\x3dhttps%3A%2F%2Fen.wikipedia.org%2Fwiki%2FFermi_energy\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNGF1b-Wht1h2pyW743ymD5tRw3JBw';return true;" onclick="this.href='https://www.google.com/url?q\x3dhttps%3A%2F%2Fen.wikipedia.org%2Fwiki%2FFermi_energy\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNGF1b-Wht1h2pyW743ymD5tRw3JBw';return true;">https://en.wikipedia.org/<wbr>wiki/Fermi_energy</a>, the</div><div>three dimensional case.) I would like to know how can I obtain this value (approximate) from the bulk metal unit cell. </div><div><br></div><div>Thanks</div></div><span><font color="#888888"> <p></p> -- <br> You received this message because you are subscribed to the Google Groups "cp2k" group.<br> To unsubscribe from this group and stop receiving emails from it, send an email to <a href="javascript:" target="_blank" gdf-obfuscated-mailto="wK4CyCAsBgAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp2k+uns...@googlegroups.<wbr>com</a>.<br> To post to this group, send email to <a href="javascript:" target="_blank" gdf-obfuscated-mailto="wK4CyCAsBgAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">cp...@googlegroups.com</a>.<br> Visit this group at <a href="https://groups.google.com/group/cp2k" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/group/cp2k';return true;" onclick="this.href='https://groups.google.com/group/cp2k';return true;">https://groups.google.com/<wbr>group/cp2k</a>.<br> For more options, visit <a href="https://groups.google.com/d/optout" target="_blank" rel="nofollow" onmousedown="this.href='https://groups.google.com/d/optout';return true;" onclick="this.href='https://groups.google.com/d/optout';return true;">https://groups.google.com/d/<wbr>optout</a>.<br> </font></span></blockquote></div><br><br clear="all"><br>-- <br><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr">-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=<wbr>*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=<wbr>-=*=-=*=-=*=-=*=-<br> Ari Paavo Seitsonen / <a href="javascript:" target="_blank" gdf-obfuscated-mailto="wK4CyCAsBgAJ" rel="nofollow" onmousedown="this.href='javascript:';return true;" onclick="this.href='javascript:';return true;">Ari.P...@iki.fi</a> / <a href="http://www.iki.fi/~apsi/" target="_blank" rel="nofollow" onmousedown="this.href='http://www.google.com/url?q\x3dhttp%3A%2F%2Fwww.iki.fi%2F~apsi%2F\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNG0aHwDkzSRT8XFNp-VAYw9AsYKJg';return true;" onclick="this.href='http://www.google.com/url?q\x3dhttp%3A%2F%2Fwww.iki.fi%2F~apsi%2F\x26sa\x3dD\x26sntz\x3d1\x26usg\x3dAFQjCNG0aHwDkzSRT8XFNp-VAYw9AsYKJg';return true;">http://www.iki.fi/~apsi/</a><br> Ecole Normale Supérieure (ENS), Département de Chimie, Paris<br> Mobile (F) : +33 789 37 24 25 (CH) : +41 79 71 90 935<br></div></div></div></div></div></div> </div> </blockquote></div></div>