Recent content by drummerguy

Say you have a Yukawa potential (a.k.a. screened coulomb potential) V(r) = -\frac{e^2}{r}e^{-rq} where q is the inverse screening length, how would you find the critical q for having bound states? I'm working on reproducing N.F. Mott's argument about the critical spacing of a lattice of...

It's from problem 12.2 - essentially it's valid near a maximum or minimum in the band (so you get an approximately quadratic dispersion). I haven't solved the problem yet, but I think the comment on page 568/569 about an ellipsoidal constant energy surface is key (in addition to the...