I'm currently taking a Solid State Physics class, and is currently reading about the quantum mechanical description of solids.
I then came across the following figure:
It's supposed to be the band structure for aluminium. My question is basically: How do I interpret these band structures ? I can't even see why they cut of the region from $X$ to $\Gamma$ at the dotted line in the first figure, and not in the second :/ Why is the last bit of $X$ to $\Gamma$ that you see in figure 2, not important in figure 1 ?
I understand that, the $X$, $\Gamma$, $K$, $L$ and $W$ are points of symmetry on the brillioun zone. But what does it mean for the electron(s) ? Only that they have higher energies at some points ?
I'm just having some trouble understanding what this band structure tells me, and what I'm able to see/do with it ?
So can anyone maybe explain it, maybe even easily, what I actually have to understand when I see this ?
Thanks in advance.