Nonlinear transport fingerprints of tunable Fermi-arc connectivity in magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$

TL;DR

This paper proposes that nonreciprocal charge transport measurements can directly detect Fermi arc Lifshitz transitions in magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$, enabling surface state engineering and characterization.

Contribution

It introduces a theoretical framework linking nonreciprocal transport signals to Fermi arc connectivity changes in Weyl semimetals, highlighting tunability via surface potential and symmetry considerations.

Findings

Second-order nonreciprocal signals are highly tunable by surface termination.

Sign changes in second-order conductivity indicate Fermi arc Lifshitz transitions.

Surface potential adjustments can modulate the nonreciprocal response.

Abstract

Fermi arcs in Weyl semimetals provide a unique platform for surface-state engineering, yet di rectly tracking of their evolution under surface tuning remains experimentally challenging. Here we theoretically propose that nonreciprocal charge transport can serve as a direct probe of Fermi arc Lifshitz transitions (FALT). We show that different surface terminations in Co3Sn2S2 can produce f inite and highly tunable second-order nonreciprocal signals, which can be further modulated by adjusting the surface potential. Strikingly, we show that the second-order conductivity exhibits sign changes as the Fermi arc connectivity is tuned across FALT driven by gating or chemical potential variation. This behavior arises from the chiral nature of electron velocities on the Fermi arcs, and is highly sensitive to surface termination and symmetry breaking. Our findings establish nonreciprocal transport as an electrically measurable fingerprint of FALT and propose new strategies that could be directly applied in devices for in situ engineering and detecting transport properties in topological materials.