1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Tight binding model and bandwidth

  1. May 26, 2008 #1
    According to tight binding moment, for BCC crystalographic structures (such as Fe), energy E depends on wave vector kx, ky, kz: E(x) = const - 8t cos(kx * a/2)*cos(ky * a/2)*cos(kz * a/2), where t>0 is the model parameter. What is the bandwidth W in terms of parameter t? Can you find kx, kz, and ky at the band bottom and at the band top?
  2. jcsd
  3. May 26, 2008 #2
    Well you need to find the minimum and maximum value of the band Energy - then W is the difference between them.. The easiest way is probably just by inspection.
  4. May 27, 2008 #3
    So the maximum is Emax = const + 8t when the multiplication of cos functions gives -1 and Emin = const -8t as the multiplication of cos functions gives 1. It implies that W = 8t - (-8t) = 16t. Now I should find kx,ky and kz fow which that cos functions multiplications results in 1 and -1. I have found 4 solution for 1 on the right side of the equation (having cos on the left one) and 4 solutions for -1 on the right. Is it possible? Am I right?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Tight binding model and bandwidth
  1. Tight-binding model (Replies: 0)