I've been studying electronic band structure in the NFE model, but first the free electron bands. I'm just a bit curious as to the exact interpretation of energy vs. wavevector plots. The free electron plot is parabolic. I know all physically distinct solutions lie in the 1st Brillouin Zone, but in the reduced scheme, one translates higher zones into the first. So then, one has more than one value of energy for a given k value. Does that mean that the electron, for a given k value, can have either of these energies say? These are the (quantized) energy levels? But if the only distinct solutions lie in the 1st BZ, then howcome higher zones, give rise to higher energies?? Should all energies not be decribes in the first BZ?? I hope you can see my confusion. Regardless, any help is always greatly appreciated!!! Thanks!