It comes from the renormalization of a more complex structure in terms of some on-site energies. I yet don't understand very well were it comes from (I'm sure about the dispersion relation, though), all I want to know is if what I'm doing is right or not...
Hi. What I'm trying to do is to obtain the energy spectrum from the following dispersion relation:
E^4-A·E^3+B·E^2-C·E+D-F·E^2·cos(k·a_0)^2+G·E·cos(k·a_0)^2-H·cos(k·a_0)^2 = 0
where E is the energy, k is the wave vector and a0 the distance between adjacent neighbors in a 1-Dimensional...