<p style="margin: 0px; padding: 0px;"> Hi Eric,</p><p style="margin: 0px; padding: 0px;"> sorry. I expressed my point maybe in a misleading way...I mean, i found a gap metallic (Homo is highest in energy than Lumo) but the system is reported to be a wide bandgap semiconductor (Gap > 2. eV)</p><pre wrap="">"highest occupied, lowest unoccupied level (ev): 6.1092 5.4104"</pre><p style="margin: 0px; padding: 0px;">HOMO=6.109 LUMO=5.4104 (as far as I understand)....the gap is 0.7 eV only if you switch HOMO and LUMO<br></p><p style="margin: 0px; padding: 0px;">The structure is the experimental one I found from a previous paper and it was optimized with Gaussian PBC<br></p><p style="margin: 0px; padding: 0px;"><br></p><p style="margin: 0px; padding: 0px;">Thanks,</p><p style="margin: 0px; padding: 0px;">G<br></p><p style="margin: 0px; padding: 0px;"> <br></p>
<blockquote>
----Messaggio originale----<br>
Da: germaneau@gucas.ac.cn<br>
Data: 03/12/2011 16.32<br>
A: "giacsport@libero.it"<giacsport@libero.it>, "PWSCF Forum"<pw_forum@pwscf.org><br>
Ogg: Re: [Pw_forum] metallic BP?<br>
<br>
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Hey Giacomo,<br>
<br>
Forgive my ignorance but why do you say that the "scf" calculation
is a system that "should be" metallic
?<br>
To me it has a band gap of .7 ev.<br>
What do you mean by wide band gap semiconductor
? <br>
What band gap value do you expect to get?<br>
May be the wide band gap behavior you mention does not occur at 0K.<br>
I guess you double checked whether your system is fully relaxed.<br>
<br>
Éric.<br>
<br>
On 12/02/2011 09:20 PM, <a class="moz-txt-link-abbreviated" href="mailto:giacsport@libero.it" mce_href="mailto:giacsport@libero.it">giacsport@libero.it</a> wrote:
<blockquote cite="mid:3375660.7676171322878802207.JavaMail.root@wmail28" type="cite">
<pre wrap="">Dear All,
I am doing calculations on a 2 atom primitive cell of Boron
Phosphide. What I obtain from the "scf" calculation is a system that "should
be" metallic.... Indeed
"highest occupied, lowest unoccupied level (ev): 6.1092
5.4104" -->( As far as I understand, Homo lies 0.7 eV above the
LUMO)
but of course this system is a wide-gap semiconductor.
I am not able to figure out the reason for such behaviour. I have tested the
same system (rhombohedral cell, a=b=c=6.06 Bohr, alpha=beta=gamma=60deg) in
several machines finding always the same result. I attach the input file and
the header of the two pseudos (USPP/GGA) I am using.
Thanks in advance for any comments.
My best,
Giacomo
&control
calculation = 'scf'
restart_mode='from_scratch',
prefix='BP',
tprnfor = .true.,
tstress = .true.,
wf_collect=.true.,
pseudo_dir='/home/giacomo/GGA/',
outdir='/home/giacomo/GGA/'
/
&system
ibrav= 4, celldm(1) =6.061296108, celldm(3)=1,
nat= 2, ntyp= 2,
ecutwfc =50., nbnd = 50,
/
&electrons
diagonalization='david'
mixing_mode = 'plain'
mixing_beta = 0.7
conv_thr = 1.0d-8
/
ATOMIC_SPECIES
B 10.811 B.UPF
P 30.974 P.UPF
ATOMIC_POSITIONS (crystal)
B 0.0 0.0 0.0
P 0.25000 0.25000 0.250000
K_POINTS (automatic)
6 6 6 0 0 0
For BORON:
<PP_INFO>
Generated using Vanderbilt code, version 7 3 5
Author: unknown Generation date: 20 6 2004
Automatically converted from original format
0 The Pseudo was generated with a Non-Relativistic Calculation
1.00000000000E+00 Local Potential cutoff radius
nl pn l occ Rcut Rcut US E pseu
2S 2 0 2.00 10.00000000000 1.50000000000 -0.69693392995
2P 2 1 1.00 10.00000000000 1.53000000000 -0.26855658626
</PP_INFO>
<PP_HEADER>
0 Version Number
B Element
US Ultrasoft pseudopotential
T Nonlinear Core Correction
SLA PW GGX GGC PW91 Exchange-Correlation functional
3.00000000000 Z valence
-5.70038942945 Total energy
0.0000000 0.0000000 Suggested cutoff for wfc and rho
1 Max angular momentum component
781 Number of points in mesh
2 4 Number of Wavefunctions, Number of Projectors
Wavefunctions nl l occ
2S 0 2.00
2P 1 1.00
</PP_HEADER>
---------------------------------
For PHOSPHORUS
<PP_INFO>
Generated using Vanderbilt code, version 7 3 5
Author: unknown Generation date: 20 6 2004
Automatically converted from original format
1 The Pseudo was generated with a Scalar-Relativistic Calculation
1.60000000000E+00 Local Potential cutoff radius
nl pn l occ Rcut Rcut US E pseu
3S 3 0 2.00 10.00000000000 1.70000000000 -1.03015496458
3P 3 1 3.00 10.00000000000 1.70000000000 -0.40774343239
</PP_INFO>
<PP_HEADER>
0 Version Number
P Element
US Ultrasoft pseudopotential
T Nonlinear Core Correction
SLA PW GGX GGC PW91 Exchange-Correlation functional
5.00000000000 Z valence
-17.57767183737 Total energy
0.0000000 0.0000000 Suggested cutoff for wfc and rho
2 Max angular momentum component
903 Number of points in mesh
2 5 Number of Wavefunctions, Number of Projectors
Wavefunctions nl l occ
3S 0 2.00
3P 1 3.00
</PP_HEADER>
------------------------------------------
Giacomo Giorgi
Department of Chemical System Engineering,
School of Engineering, The University of Tokyo
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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<a href="http://www.linkedin.com/pub/%C3%A9ric-germaneau/30/931/986">Dr.
Éric Germaneau</a><br>
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Graduate University of Chinese Academy of Sciences<br>
College of Physical Sciences<br>
Yuquan Road 19A<br>
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