Fermi-arc diversity on surface terminations of the magnetic Weyl semimetal Co3Sn2S2

TL;DR

This study investigates how different surface terminations of the magnetic Weyl semimetal Co3Sn2S2 affect Fermi-arc surface states, revealing the influence of surface potential on topological features and their connectivity.

Contribution

It demonstrates the impact of three distinct surface terminations on Fermi-arc contours and Weyl node connectivity in Co3Sn2S2, confirming its classification as a time-reversal symmetry broken Weyl semimetal.

Findings

Surface termination alters Fermi-arc contours and connectivity.

Sn surface shows intra-Brillouin zone Weyl node connectivity.

S surface Fermi-arcs overlap with non-topological states.

Abstract

Bulk-surface correspondence in Weyl semimetals assures the formation of topological "Fermi-arc" surface bands whose existence is guaranteed by bulk Weyl nodes. By investigating three distinct surface terminations of the ferromagnetic semimetal Co3Sn2S2 we verify spectroscopically its classification as a time reversal symmetry broken Weyl semimetal. We show that the distinct surface potentials imposed by three different terminations modify the Fermi-arc contour and Weyl node connectivity. On the Sn surface we identify intra-Brillouin zone Weyl node connectivity of Fermi-arcs, while on Co termination the connectivity is across adjacent Brillouin zones. On the S surface Fermi-arcs overlap with non-topological bulk and surface states that ambiguate their connectivity and obscure their exact identification. By these we resolve the topologically protected electronic properties of a Weyl semimetal and its unprotected ones that can be manipulated and engineered.