Kronig-Penney model

Okay kiddo, imagine you have a long line of little beads. We call this our lattice. And every bead can either move up or down.

Now, let's say we have a little toy ball that we push through the lattice. This ball can either travel through the beads that are up, or the beads that are down.

But here's the thing - some beads are special. They are like walls that the ball can't get through. These walls are placed in a special pattern, so they create little sections where the ball can only travel through certain beads.

Now, let's talk about electrons. They act like little balls in the world of physics. And just like our toy ball, they can be pushed through our lattice of beads (which we call a crystal).

The Kronig-Penney model uses this idea of a crystal lattice with certain barriers to help us understand how electrons move through a solid material. It helps us predict important things like how easily electricity can flow through a substance, and how light can be absorbed or reflected by that substance.

So there you have it, a simple explanation of the Kronig-Penney model.