Advanced Solid State Physics

O

P 2

P 1

G 2

2

k 2

G 1

2

k 1

Figure 8: Brillouin zone

Now we take the inner product ofGCwith some vectork 1. If this product equalsG
2
2 thenk^1 will fall
on this plane and the diffraction condition is fullfilled. So a wave will be diffracted if the wavevector
kends on this plane (or in general on one of the planes).

The space around the origin which is confined by all those planes is called the1st Brillouin zone.