# Considering spin in the transport of nanoscale devices

1. ### simsCity

7
Hi,

The transmission of nano devices are generally done without cosidering the spin polarization. However, as I saw in some papers, the effect of spin is sometimes included. How can I decide to use spin or not when simulationg transmission of nanoscale devices?

2. ### M Quack

847
It takes quite some effort to produce spin polarization in nano devices. Spins get scattered and eventually average out to a 50%/50% non-magnetic population. The length scale (spin diffusion length) for this depends on the material and heavy atom impurities, but in general it is quite short.

So unless you make an effort to spin-polarize your device, e.g. by direct contact with a ferromagnetic layer or irradiation with circular polarized light you can probably neglect spin effects.

http://en.wikipedia.org/wiki/Spintronics

3. ### simsCity

7
Thanks a lot.