Is there some way in which I could plot energy bands using Mathematica in a manner that is given in the image below? I have $E$ as a function of $k_x$ and $k_y$. How can the plot given below be made with these specific points on the $(k_x,k_y)$ axis?
My function for the energy $E$ is:
energy[kx_,ky_]:=Sqrt[1-(Cos[kx/2]Cos[ky/2])^2]
and I can plot parts of the graph with something like:
Plot[energy[kx,0],{kx,0,Pi}]
Plot[energy[kx,0],{kx,Pi,2 Pi}]
How do I stitch these together?