like a normal metal (i understand that part: delocalised electrons) what i'm confused about is the semimetal part
So, if a metal has a band of electrons that are completely free to move (delocalised) a semimetal has states in which this occurs and states in which it doesn't. It has some electrons with partial freedom that can express this freedom under certain circumstances. So in some situations it behaves like a metal and some situations when it behaves like a non-metal.
So, if a metal has a band of electrons that are completely free to move (delocalised) a semimetal has states in which this occurs and states in which it doesn't. It has some electrons with partial freedom that can express this freedom under certain circumstances. So in some situations it behaves like a metal and some situations when it behaves like a non-metal.