Lecture 15: Continuity Equations

We derive the Einstein relations, which connect the conductivity with the diffusion coefficient. This is far more exciting than it sounds, because it's a consequence of the far-reaching fluctuation-dissipation theorem. Another instance of this theorem happens with Brownian motion, and the applet we used in class can be found at We also derive the continuity equations in a semiconductor, and see how fast they can screen a stray charge that may be produced by, say, thermal fluctuations. We highlight 2 applications of semiconductors: LED's and solar cells. We discuss a bit the impending energy challenge, referring to a talk by Nobel Laureate Richard Smalley. Sadly, he has passed away. Lecture Audio

You can listen to Lecture 15: Continuity Equations online on Radio and Podcast. Open the player on this page to stream the available audio.

Lecture 15: Continuity Equations is an episode from Solid State Physics by Prof. Carlson.

The episode duration depends on the source podcast feed and may not always be available.

This episode was published on Mar 7, 2006.

Yes. Use the heart button on the episode page to add it to your favorite episodes list.

Yes. This page shows related episodes from Solid State Physics when more episodes are available from the podcast feed.