(a+b) = 5 Å (corresponds to atomic spacing) a=1Å
U0 = 2.4 eV
Second lowest energy band k = π/(2(a+b))
b)Show that the wavefunction is the same if k = 5π/(2(a+b)) (this would be in the second Brillouin zone)
c) What is the energy of this state? Is E>U0 or is E<U0?