Tuesday, September 25, 2018 - 3:45pm to 4:45pm
1080 Physics Research Building - Smith Seminar Room - reception at 3:30 pm in the Atrium
We provide a perspective on the recent emergence of “topological spintronics,” which relies on helical Dirac electrons on the surfaces of solids with strong spin-orbit coupling ..When timereversal symmetry is broken by ferromagnetic order, the helical Dirac states transition to chiral edge states . This is a realization of Haldane’s Chern insulator phase of matter, characterized by a precisely quantized Hall conductance and ballistic edge transport without a magnetic field, even in systems with significant electronic and magnetic disorder [3,4]. The interplay between these edge states, dissipative channels and magnetic order appears to yield a condensed matter realization of quantum tunneling out of a ‘false vacuum’ . Interesting opportunities are also emerging for patterning and manipulating the edge states using optical techniques . On a more pragmatic note, the helical spin texture of the surface states also leads to efficient spincharge conversion at room temperature [6,7], allowing one to envision novel devices for universal memory and spin-based logic.
 M. Neupane, A. Richardella et al., Nature Communications 5, 3841 (2014).
 A. Kandala, A. Richardella, et al., Nature Communications 6, 7434 (2015).
 E. Lachman et al., Science Advances 1, e1500740 (2015).
 M. Liu et al., Science Advances 2, e1600167 (2016).
 A. L. Yeats et al. PNAS (online 12 September, 2017).
 A. Mellnik, J. S. Lee, A. Richardella et al., Nature 511, 449 (2014).
 H. Wang et al., Physical Review Letters 117, 076601 (2016).