Thank you Mr. Robert for your kind response. I will include the verbosity='high' and repeat the calculations. However, you made mention that, when i plotted the DOS there is need to shift my Fermi level to zero; that i did not understand very well. My question is, How to shift my Fermi to zero?. Secondly, I always see my Fermi energy at the end of my scf calculation.'' the Fermi energy is -2.0508'', before total energy line. Does it mean -2.0508 is my actual Fermi energy? because the zero point in the DOS graph is just a reference point. Lastly, for my plotting software, i used Qtiplot. Usually, after my ./dos.x input and output, i take my 'dos'? directly to plot my DOS. Therefore, I don't know if you or someone can help with some guide about it.
Once again thank you and Best regards. Shamsu Abubakar Postgraduate student Department of Physics University Putra Malaysia ________________________________ From: Robert Hembree <hembreerofphysics at gmail.com> To: 'Shamsu Abubakar' <say457 at yahoo.co.uk>; 'PWSCF Forum' <pw_forum at pwscf.org> Sent: Friday, 5 April 2013, 1:17 Subject: RE: [Pw_forum] Fermi energy reference point shift from 0 to -2 Dear Shamsu ? Your input file and parameters are fine. When you plot the DOS you need to shift your? Fermi level to zero if you want the gap to show up at zero. Add the line verbosity = ?high? to the control part of your input file and run pw.x again. Then you can grep your output file less scf.out | grep ?Fermi energy? ? You should get a line that looks like this: the Fermi energy is??? -1.6709 ev ? When you plot your DOS, for instance in gnuplot you would now plot ? plot ?Graph01.dos? ($1-(-1.6709)):2 w l and you should see your? plot with the bandgap and dispersion at zero. ? When you do these calculations the Fermi level will rarely show up at exactly zero. ? Robert ? From:pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] On Behalf Of Shamsu Abubakar Sent: Wednesday, April 03, 2013 8:23 PM To: pw_forum at pwscf.org Subject: [Pw_forum] Fermi energy reference point shift from 0 to -2 ? Dear Q.E Users. I have a system of 4x4 graphene supercell, comprising 32 carbon atoms. I sucessfully run all the calculations i.e scf,nscf and other postprocessing such as DOS and PDOS. But the main problem i'm facing currently is on the density of state. Usually, i consider zero to be my fermi reference energy point in my ./dos.x input file, forexample,from -10 and 10 as my Emin and Emax respectivily. For pristine graphene,i expect to always see the dispersion at the zero vicinity, showing a semi metallic behavior, but surprisingly, its always moving away from zero to around -2, in the valence band side which i knew is unsual for pristine graphene. However, when i combine graphene with GaAs nanostructure, most of the interesting properties interms of orbitals contributions (PDOS), also resides on similar point -2. That is some of the contributions that are supposed to be seen at the vicinity of the fermi level, now moved to another point -2. Also, i consider changing the smearing from marzari-vanderbilt to Fermi- Dirac, but similar properties were observed. I decided to consider only 1x1, and 2x2 graphene supercell alone, still similar properties i observed also. In fact, i even consider changing my pseudopotential from pw91 to pbe.rrkjus still no progress. My problem now, i don't know what really causes these shift from 0 to -2. I attached one of my graphene scf input file for your verification and advice. ? ?&CONTROL ??????????????????? title = 'Graphene monolayer01', ????????????????????? prefix = 'Graph01', ???????????????? calculation = 'scf' , ??????????????? restart_mode = 'from_scratch' , ???????????????????? outdir = '/home//???/espresso-4.1.2/bin/' , ????????????????? pseudo_dir = '/home//???/???/espresso-4.1.2/upf_files/' , ?????????????? ???????????????????? tstress = .true. , ???????????????????? tprnfor = .true. , ?/ ?&SYSTEM ?????????????????????? ibrav = 4, ?????????????????? celldm(1) = 18.59490373, ?????????????????? celldm(3) = 1.80, ???????????????????????? nat = 32, ??????????????????????? ntyp = 1, ???????????????????? ecutwfc = 34.D0 , ????????????????? tot_charge = 0.000000, ???????????????? occupations = 'smearing' , ???????????????????? degauss = 0.02 , ??????????????????? smearing = 'fermi-dirac' , ???????????????????? ?/ ?&ELECTRONS ??????????????????? conv_thr = 1.D-8 , ???????????????? mixing_beta = 0.7D0 , ?/ ATOMIC_SPECIES ???? C?? 12.00000? C.pw91-van_ak.UPF ??? ATOMIC_POSITIONS (angstrom) C??????? 1.229999657?? 0.709326753?? 1.999999753 C??????? 2.459999165?? 1.419486000?? 1.999999874 C??????? 3.689999208?? 0.709327391?? 1.999999822 C??????? 4.920000000?? 1.419486496?? 1.999999944 C??????? 4.920000000?? 2.839880146?? 2.000000125 C??????? 6.149999990?? 3.549976521?? 1.999999907 C??????? 3.690000010?? 3.549976521?? 1.999999907 C??????? 2.459999764?? 2.839879152?? 2.000000067 C??????? 6.150000792?? 0.709327391?? 1.999999822 C??????? 7.380000835?? 1.419486000?? 1.999999874 C??????? 7.380000236?? 2.839879152?? 2.000000067 C??????? 8.610000005?? 3.549975943?? 1.999999891 C??????? 8.609999654?? 4.970023341?? 2.000000208 C??????? 9.840000000?? 5.680120078?? 2.000000200 C??????? 7.379999382?? 5.680120770?? 2.000000152 C??????? 6.149999800?? 4.970024086?? 2.000000150 C??????? 4.920000000?? 5.680121474?? 2.000000132 C??????? 3.690000200?? 4.970024086?? 2.000000150 C??????? 8.610000343?? 0.709326753?? 1.999999753 C??????? 9.840000000?? 1.419485253?? 1.999999874 C??????? 9.840000000?? 2.839878353?? 2.000000070 C?????? 11.069999995?? 3.549975943?? 1.999999891 C?????? 11.070000346?? 4.970023341?? 2.000000208 C?????? 12.300000618?? 5.680120770?? 2.000000152 C?????? 12.300001137?? 7.100514050?? 2.000000166 C?????? 13.530000464?? 7.810673002?? 1.999999744 C?????? 11.070000830?? 7.810672948?? 1.999999928 C??????? 9.840000000?? 7.100514025?? 2.000000287 C??????? 8.609999170?? 7.810672948?? 1.999999928 C??????? 7.379998863?? 7.100514050?? 2.000000166 C??????? 6.149999536?? 7.810673002?? 1.999999744 C??????? 4.920000000?? 7.100514261?? 2.000000041 ????? K_POINTS automatic ? 6 6 1?? 0 0 0? ? Thank you for your kind response. ? Shamsu Abubakar Postgraduate student Department of Physics University Putra Malaysia -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20130405/8e77a677/attachment.html
