Robert, Rutile is a widely studied system, so there should be accurate plane-wave calculation in the literature for you to compare your result. LDA can indeed seriously underestimate band gaps, and even render insulators metallic sometimes. I recommend you do a search in the literature and see if other PW or Siesta/local orbital calculations yield the same result.
Marcos On Tue, Jun 15, 2010 at 6:18 PM, Koch, Robert J <[email protected]> wrote: > Hello All, > > I'd greatly appreciate any advice on the following: > > I'm trying to calculate the band gap of TIO2 (Rutile). I have attached my > fdf file, my pseudo .psf files as well as their input .inp files. > > When I run this and use the eig2dos utility to plot density of states, I > see a band gap of about 1.4 eV which is far too low (should be about 3.3 > eV). I'm aware that typically DFT calculations underestimate the band gap, > but this underestimation seems like a little much. Can anyone make any > recemendations as to how to improve my calculation? I'm quite stuck and not > sure how to proceed. > > Thanks in advance! > Rob Koch >
