Two-dimensional (2D) surface of the topological materials is an attractive channel for the electrical conduction reflecting the linearly-dispersive electronic bands. Thickness-dependent sheet conductance measurement is a reliable method to evaluate the 2D and three-dimensional (3D) electrical conducting channel separately but has rarely been applied for Weyl semimetals. By applying this method to thin films of a Weyl semimetal Co₃Sn₂S₂, here we show that the 2D conducting channel clearly emerges under the ferromagnetic phase, indicating a formation of the Fermi arcs projected from Weyl nodes. Comparison between 3D conductivity and 2D conductance provides the effective thickness of the surface conducting region being estimated to be approximately 20 nm, which would reflect the Weyl feature of electronic bands of the Co₃Sn₂S₂. The emergent surface conduction will provide a pathway to activate quantum and spintronic transport features stemming from a Weyl node in thin-film-based devices.

拓扑材料的二维 (2D) 表面是反映线性色散电子带的电传导的有吸引力的通道。厚度相关的片电导测量是分别评估 2D 和 3D (3D) 导电通道的可靠方法，但很少应用于外尔半金属。通过将这种方法应用于 Weyl 半金属 Co ₃ Sn ₂ S _{2 的}薄膜，在这里我们表明 2D 导电通道清楚地出现在铁磁相下，表明从外尔节点投射的费米弧的形成。3D 电导率和 2D 电导率之间的比较提供了估计为大约 20 nm 的表面导电区域的有效厚度，这将反映 Co ₃ Sn ₂ S ₂的电子带的 Weyl 特征。突现表面传导将为激活源自薄膜器件中的 Weyl 节点的量子和自旋电子传输特征提供途径。