Discussion about this site, its organization, how it works, and how we can improve it.
in the answers of many atoms per unit cell,
it would be nice to switch the |sin(ka/2)| part with the |cos(ka/4)| part,
because the 1+cos(x) corresponds with the cos part and now it seems like its the other way around. which messes with the undersatnding of what part is the acoustic or the optical band