The fact that spin current is not conserved may be bad news, but the important thing is that we know what is going on. Things may not have gone as predicted, but at least we’ve...

When talking about the motion of charge current, you can think of the electrons as acting like a swarm of bees moving in one direction. Within that swarm, individual bees might be colliding, but momentum...

We get a diffusion of spin because we create a situation in which there will be more spin-up electrons in one place and fewer in another.

You would think that since an electron carries a spin and a charge, that their motions would be equal. But, our research shows the contrary, due to a friction-like effect known as spin Coulomb drag.

Spin Coulomb drag results because the motion of spin through the semiconductor is sensitive to collisions between electrons, whereas the transport of charge is not. When electrons bump into one another, the mutual repulsion of...