Observation of spin-polarized surface states in a nodal line semimetal SnTaS${}_2$

Abstract

The superconductor SnTaS${}_2$ is theoretically predicted to be an intriguing topological nodal line semimetal without consideration of spin-orbit coupling. By carrying out angle-resolved photoemission (ARPES) and spin-resolved ARPES measurements combined with band structure calculations, we have provided a complete picture of the electronic structure and spin polarization property for the prominent surface states of SnTaS${}_2$. The low-energy electronic states are dominated by surface states; two of them are from the S-terminated surface, while four of them are from the Sn-terminated surface. These give rise to interesting Fermi surface topology of SnTaS${}_2$: three pockets located at $\bar{\Gamma }$, $\bar{M}$ and $\bar{K}$ for the S-terminated surface and two pockets surrounding $\bar{\Gamma }$ and $\bar{K}$ for the Sn-terminated surface. We further reveal that two surface states that cross the Fermi level are spin-polarized. Since SnTaS${}_2$ is also a superconductor, our observations indicate that it may provide a new platform to explore topological superconductivity and other exotic properties.

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Cited by in corpus (1)

• Surface magnon spectra of nodal loop semimetals