Update src/8_many_atoms_sol.md

src/8_many_atoms_sol.md

@@ -76,3 +76,5 @@ pyplot.fill_between([-3*pi,3*pi], -np.abs(t1-t2), np.abs(t1-t2), color='red',alp
 pyplot.legend(loc='lower center');
 ```
 
+Notice that the red shaded area is not a part *Band structure* anymore!
+