The Quantum Hall Effect and Spintronics

          @misc{ pirsa_PIRSA:15040157,
            doi = {10.48660/15040157},
            url = {https://pirsa.org/15040157},
            author = {MacDonald, Allan},
            keywords = {Condensed Matter},
            language = {en},
            title = {The Quantum Hall Effect and Spintronics},
            publisher = {Perimeter Institute},
            year = {2015},
            month = {apr},
            note = {PIRSA:15040157 see, \url{https://pirsa.org}}
          }
          

Abstract

A series of fundamental discoveries over the past thirty years has dramatically improved our ability to read, write, and process magnetically stored information. I will briefly review some of these advances before focusing on the recently discovered and particularly promising spin-orbit torques which act on the collective spin of thin film magnetic conductors when they are placed on a substrate with strong spin-orbit interactions. Spin-orbit torques are normally interpreted in terms of the spin Hall effect, spin-current that flows perpendicular to charge current in any conductor. The spin-Hall effect in the best spin-orbit torque materials is thought to have a large contribution from states away from the Fermi energy that is insensitive to disorder and therefore referred to as intrinsic. I will argue that the physics of the intrinsic spin Hall effect is quite closely related to the physics of the quantum Hall effect, and on this basis speculate on strategies to find the material combinations that optimize the spin-orbit torque effect.