Observation of linearly dispersive edge modes in a magnetic Weyl semimetal Co₃Sn₂S₂

The physical realization of Chern insulators is of fundamental and practical interest, as they are predicted to host the quantum anomalous Hall effect (QAHE) and chiral edge states which carry dissipationless current. Realization of the QAHE state has however been challenging due to the complex heterostructures and sub-Kelvin temperatures required. Magnetic Weyl semimetals, essentially stacks of Chern insulators with inter-layer coupling, may provide a new platform for the higher temperature realization of robust 2D QAHE edge states. In this work we present a combined scanning tunneling spectroscopy and theoretical investigation of a newly discovered magnetic Weyl semimetal, Co₃Sn₂S₂. Using numerical simulations we find that chiral edge states can be localized on partially exposed Kagome planes on the surface of a Weyl semimetal. As such, our STM dI/dV maps on narrow kagome Co₃Sn terraces show linearly dispersing quantum well-like states, which can be attributed to hybridized chiral edge modes. Our results suggest a new paradigm for studying chiral edge modes in time-reversal breaking Weyl semimetals. More importantly, this work leads a practical route for realizing higher temperature QAHE.