Topological Spintronics

Abstract: The past decade has witnessed an explosion of activity in exploring the properties of topological quantum materials whose band structure has interesting features arising from the nexus of topology, spin-orbit coupling, and fundamental symmetries. A key characteristic of the band structure in many of these materials is the ‘spin-momentum correlation’ in helical Dirac states. This leads to the notion of ‘topological spintronics’ devices that seek to exploit efficient spin-charge interconversion for low power, non-volatile magnetic random access memory technologies. This talk provides an overview of the genesis of topological spintronics and the current state of this field. By synthesizing epitaxial topological insulator/ferrimagnetic insulator heterostructures, we examine the optimal conditions under which efficient spin-charge conversion occurs in a topological insulator under ambient conditions. These heterostructures also create opportunities for realizing complex spin textures such as skyrmions. Finally, we discuss recent experiments that examine whether topological semimetals might provide an attractive route toward energy efficient spintronic devices.

This work is sponsored in part by SMART, a funded center of nCORE, a Semiconductor Research Corporation (SRC) program sponsored by NIST, the Institute for Quantum Matter under DOE EFRC grant DE-SC0019331, and the Penn State Two-Dimensional Crystal Consortium-Materials Innovation Platform (2DCC-MIP) under NSF Grant No. DMR- 1539916.