Disorder-induced helical phase in magnetic topological insulators
ORAL
Abstract
In magnetically doped thin-film topological insulators, aligning the magnetic moments generates a quantum anomalous Hall phase with a single chiral edge state. We study the de-magnetization process and show that disorder from randomly oriented magnetic moments can produce a quantum-spin-Hall-like phase with counter-propagating helical edge modes protected by a unitary reflection symmetry. This phase is analogous to the quantum spin Hall effect observed in the zeroth Landau level of graphene, which is also protected by a unitary symmetry (spin rotation). We show that introducing superconductivity, combined with selective breaking of reflection symmetry by a gate, allows for creation and manipulation of Majorana zero modes via purely electrical means.
*We acknowledge support from the Army Research Office under Grant Award W911NF-17-1-0323 (J.A.); the NSF through grants DMR-1723367 (J.A.); an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation through Grant GBMF1250 (J.A.); the Caltech Institute for Quantum Information and Matter, and the Walter Burke Institute for Theoretical Physics at Caltech (A.H. and J.A.).
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Presenters
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Arbel Haim
- Caltech