The analysis of Bloch waves given in the previous chapter is closely related to the classic analysis of waves that you’ve seen in condensed-matter physics or semiconductor theory. In semiconductors in particular, we often talk of band diagrams and indirect or direct band gaps. We use terms like conduction bands, valence bands, and Brillouin-zone boundaries (BZBs). We visualize these quantities by drawing diagrams of
), the electron energy (which is a function of
, the wave vector.