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Dear Mehmet and Hui Wang,<br>
<br>
That's what I did.<br>
From my calculations the occupied and unoccupied bands touch only at
K point.<br>
I was just confused because the scf calculation does not output a
zero gap.<br>
I mean the line "highest occupied, lowest unoccupied level" shows
two different values and I expected them to be equal.<br>
So, it seems I did not too bad in fact. <br>
But how to experimentally get a zero gap then?<br>
Thanks,<br>
<br>
Eric.<br>
<br>
On 03/09/2011 07:02 AM, Mehmet Topsakal wrote:
<blockquote
cite="mid:AANLkTik18472oYR_2Fqxd7NUv50Krez=F-RQKSWpYLEe@mail.gmail.com"
type="cite">
<meta charset="utf-8">
Dear <span style="border-collapse: collapse; font-family:
arial,sans-serif; font-size: 13px;">Eric,</span>
<div><br>
</div>
<div><span style="border-collapse: collapse; font-family:
arial,sans-serif; font-size: 13px;"></span>In addition, if you
select 18x18x1 kpoints, your mesh should include both K and M
points.</div>
<div><br>
</div>
<div>But for a band-structure calculation, you should arrange a
kpoints list along special directions, such as from
GAMMA-to-M-to-K-to-GAMMA, and do a nscf calculation....</div>
<div><br>
</div>
<div><br>
<div> <br>
<div class="gmail_quote">On Wed, Mar 9, 2011 at 11:28 AM,
xirainbow <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:nkxirainbow@gmail.com">nkxirainbow@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;"> Dear <span style="border-collapse:
collapse; font-family: arial,sans-serif; font-size:
13px;">Eric:</span>
<div><font face="arial, sans-serif"><span
style="border-collapse: collapse;">The occupied and
unoccupied bands touch each other only at M point(or
K point, I forget it).</span></font></div>
<div><font face="arial, sans-serif"><span
style="border-collapse: collapse;">You must include
this point in you k-mesh.</span></font></div>
<div><font face="arial, sans-serif"><span
style="border-collapse: collapse;">Furthermore, if
you include spin-orbital coupling, the band gap will
be opened at this point.<br>
</span></font><br>
<div class="gmail_quote">
<div>
<div class="h5">On Thu, Mar 10, 2011 at 1:30 AM,
Eric Germaneau <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:germaneau@gucas.ac.cn"
target="_blank">germaneau@gucas.ac.cn</a>></span>
wrote:<br>
</div>
</div>
<blockquote class="gmail_quote" style="margin: 0pt 0pt
0pt 0.8ex; border-left: 1px solid rgb(204, 204,
204); padding-left: 1ex;">
<div>
<div class="h5">
<div bgcolor="#ccccff" text="#000000"> Dear all,<br>
<br>
I'm trying to compute graphene's band gap but
get stuck.<br>
From my understanding a scf calculation should
provide the same energy for the highest
occupied and lowest occupied level which means
a zero gap.<br>
I played with the number a kpoints a finally
got a band gap of 0.57 which is not null.<br>
The scf convergence looks good.<br>
I'm not (yet) an expert in DFT calculation so
may did something wrong or misunderstood
something here.<br>
So, I wonder if someone has already
successfully performed such calculation.<br>
I have attached my input file.<br>
Thanks in advance,<br>
<br>
Eric.<br>
<br>
<div>-- <br>
<center> <font color="#946e8c"> <em> Be
the change you wish to see in the
world<br>
</em> <small> <font color="#946e8c"> —
Mahatma Gandhi —<br>
</font></small> <br>
<a moz-do-not-send="true"
href="mailto:germaneau@gucas.ac.cn"
target="_blank">Dr. Éric Germaneau</a><br>
<br>
College of Physical Sciences<br>
Graduate University of Chinese Academy
of Sciences<br>
Yuquan Road 19A<br>
Beijing 100049<br>
China<br>
<br>
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____________________________________<br>
Hui Wang<br>
School of physics, Fudan University, Shanghai, China<br>
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<br>
-- <br>
<br>
Mehmet Topsakal (Ph.D. Student)<br>
UNAM-Institute of Materials Science and Nanotechnology.<br>
Bilkent University. 06800 Bilkent, Ankara/Turkey<br>
Tel: 0090 312 290 3527 ; Fax: 0090 312 266 4365<br>
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href="http://www.researcherid.com/rid/A-5015-2010"
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<br>
<div class="moz-signature">-- <br>
<center> <font color="#946e8c"> <em> Be the change you wish to
see in the world<br>
</em> <small> <font color="#946e8c"> — Mahatma Gandhi —<br>
</font></small> <br>
<a href="mailto:germaneau@gucas.ac.cn">Dr. Éric Germaneau</a><br>
<br>
College of Physical Sciences<br>
Graduate University of Chinese Academy of Sciences<br>
Yuquan Road 19A<br>
Beijing 100049<br>
China<br>
<br>
<small> <em> <font style="color: rgb(73, 136, 72);"
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