MaximumPC had an article about this, but as with many other things I read in MaxPC, I always have to look through my issues strewn all over the place.🙂
It had to do with some quantum tunnelling effect or something. I don't remember the name of the effect. I think it involves electronic "holding areas" letting certain numbers of electrons in and out; the number in the holding cell dictates 1 or 0. But again, I'd have to find the issue again for the exact reason.