Topological Magnetoelectric Switching on the Atomic Scale

Abstract

Intrinsic magnetic topological insulators from MnBi2Te4 family promise realization of axion insulator, a theoretically predicted state of matter capable to mutually convert electric and magnetic signals, and whose properties are reminiscent of cosmological axion dark matter. Here we report the first experimental realization of room-temperature axionic single-spin switch in topological metamaterial MnBi2Te3. The metamaterial was in situ created in the scanning tunneling microscopy (STM) experiment by removing Te atomic layer from MnBi2Te4 surface using STM tip. Room temperature STM study of MnBi2Te3 revealed atomic scale variations of exchange gap and formation of nanoscale spin bubbles pinned at subsurface defects. We found that individual spin states in MnBi2Te3 can be reversibly switched using local electric field of STM tip with magnetoelectric response comparable to the theoretically predicted response of axion insulator. The observed topological surface magnetism develops significantly above bulk Néel temperature.

arXiv comment24 pages, 5 figures

References in corpus (17)

• Topological Insulators
• Topological Field Theory of Time-Reversal Invariant Insulators
• Magnetic-field-induced quantized anomalous Hall effect in intrinsic magnetic topological insulator MnBi${}_2$Te${}_4$
• Topological axion states in magnetic insulator MnBi${}_2$Te${}_4$ with the quantized magnetoelectric effect
• Quantized Faraday and Kerr rotation and axion electrodynamics of a 3D topological insulator
• Imaging Dirac-Mass Disorder from Magnetic Dopant-Atoms in the Ferromagnetic Topological Insulator Cr${}_x$(Bi${}_{0.1}$Sb${}_{0.9}$)${}_{2-x}$Te${}_3$
• Electrically controllable surface magnetism on the surface of topological insulator
• Surface states and Rashba-type spin polarization in antiferromagnetic MnBi${}_2$Te${}_4$
• Surfaces of Axion Insulators
• A Proposal to Detect Dark Matter Using Axionic Topological Antiferromagnets
• Electronic states and magnetic response of MnBi2Te4 by scanning tunneling microscopy and spectroscopy
• Magnetic imaging of antiferromagnetic domain walls
• Proximity-induced Majorana hinge modes in antiferromagnetic topological insulators
• Evidence for exchange Dirac gap in magneto-transport of topological insulator-magnetic insulator heterostructures
• Colossal anisotropy in diluted magnetic topological insulators
• Spin Stiffness and Domain Walls in Dirac-Electron Mediated Magnets
• Subtle metastability of the layered magnetic topological insulator MnBi2Te4 from weak interactions