Advances in Spintronics

Tuesday, February 14, 2012 – 3:30pm
Reiss 502
Mark Johnson
Naval Research Laboratory

The manipulation of conduction electron spin in metals and semiconductors offers new dimensions for basic and applied research, along with the potential for new capabilities for electronics technology. This field, called Spintronics, continues to be very active. After a brief review of the basic principles that underly prominent device families, the talk will focus on the physics of the Spin Injected Field Effect Transistor (Spin FET). Two decades ago, Datta and Das [1] predicted that a gate voltage applied to spin polarized carriers in a two dimensional electron gas (2DEG) would induce spin precession that could be observed as a conductance oscillation. We have observed the Datta – Das oscillation in a high mobility InAs Spin FET with ferromagnetic metal electrodes. This effect is a unique manifestation of special relativity, and the Spin FET also offers the ability to study spin coherence and quantum size effects. For those who wish to consider spin as a state variable for future generation electronics, our experiment has shown that spin can be controlled by the same parameter (voltage) that’s used to control the charge state.

[1] S. Datta and B. Das, Appl. Phys. Lett. v. 56, 665 (1990).
[2] H.C. Koo, J.H. Kwon, J. Eom, J. Chang, S.H. Han and M. Johnson, Science v. 325, 1515 (2009).

Host: Paola Barbara