Hi all I am reading about conductors and energy bands, and I undertand the math. I just need for it to be more intuitive. This is how I have understood it: We look at e.g. a semiconductor at zero temperature made of silicon . Since silicon has 4 valence electrons, these 4 electrons of one Si-atom are in (covalent?) bonds with the electrons of the other Si-atoms. Now if we turn on the heat, then the electrons are excited to the conduction band, but what happens to the electron and the bonds? Do the bonds stay the same? Do the electrons get excited to a higher shell or what?