Evidences of Topological Surface States in the Nodal-Line Semimetal SnTaS<sub>2</sub> Nanoflakes
Wenshuai Gao, Mengcheng Zhu, Dong Chen, Xin Liang, Yuelong Wu, Ankang Zhu, Yuyan Han, Liang Li, Xue Liu, Guolin Zheng, W. J. Lu, Mingliang Tian
Abstract
Exploring the topological surface state of a topological semimetal by the transport technique has always been a big challenge because of the overwhelming contribution of the bulk state. In this work, we perform systematic angular-dependent magnetotransport measurements and electronic band calculations on SnTaS 2 crystals, a layered topological nodal-line semimetal. Distinct Shubnikov–de Haas quantum oscillations were observed only in SnTaS 2 nanoflakes when the thickness was below about 110 nm, and the oscillation amplitudes increased significantly with decreasing thickness. By analysis of the oscillation spectra, together with the theoretical calculation, a two-dimensional and topological nontrivial nature of the surface band is unambiguously identified, providing direct transport evidence of drumhead surface state for SnTaS 2 . Our comprehensive understanding of the Fermi surface topology of the centrosymmetric superconductor SnTaS 2 is crucial for further research on the interplay of superconductivity and nontrivial topology.