Update 12_band_structures_in_higher_dimensions_solutions.md

src/12_band_structures_in_higher_dimensions_solutions.md

@@ -42,7 +42,7 @@ $$ E = \varepsilon_0 -2t_1 \cos(k_x a_x) -2t_2 \cos(k_y a_y)$$
 
 Monovalent -> half filled bands -> rectangle rotated 45 degrees.
 
-Much less than 1 electron per unit cell -> almost empty bands -> circular.
+Much less than 1 electron per unit cell -> almost empty bands -> elliptical.
 
 ```python
 def dispersion2D(N=100, kmax=pi, e0=2):