*2010/9/21 Marcos Veríssimo Alves <[email protected]> * > > *Zhendong,* > * > * > *Supposing that you want to plot the wavefunctions corresponding to the > HOMO and LUMO (you don't make it very clear), what you want is in either the > WF files or the LDOS file. The easiest thing to do is:* > * > * > *1) Open the EIG file, and check where the Fermi level, EF is.* > *2) Since you have (I suppose) a molecule, the HOMO will be the energy > level right below EF, and the LUMO will be the energy level right above EF. > Take note of those energy levels.* > *3) You can obtain a spatial distribution of charge for the HOMO and LUMO > by calculating the LDOS around the levels that you have just obtained. Since > you have something only at Gamma anyway, your wavefunctions will be real and > the LDOS will be closely related to them. However, if you need phases and > signs of the wavefunctions, then you have to really plot the wavefunctions > themselves - I have never done it, but the manual should provide you with > sufficient information.* > * > * > *If you decide to calculate the LDOS, be careful to NOT set the energy > range in such a way that it goes below beyond {E[HOMO] + E[HOMO-1]}/2 (or > {E[LUMO] + E[LUMO+1]}/2).* > * > * > *Marcos* > > > > > when i try the same for a planar graphene structure of 2.5 nm by 2.5 nm (having around 250 atoms) i get a band gap of 0.06 eV(HOMO LUMO method) while if i plot the band structure using gnubands i get a band gap of 0.41 eV. Why is there a difference and which method is correct
-- regards deepak 3rd Year Under Graduate Electronics Design and Manufacturing IIIT (D&M),Kancheepuram IIT Madras Campus,Chennai
