Observation of topological nodal fermion semimetal phase in ZrSiS

TLDR

Condensed matter physics seeks new topological phases, with recent Dirac and Weyl semimetal discoveries motivating searches for additional exotic states. The study systematically investigates ZrSiS using ARPES to probe its topological nodal semimetal properties. The authors performed systematic ARPES measurements across the Brillouin zone of ZrSiS to map its electronic structure. ARPES mapping revealed multiple Fermi pockets and confirmed a spinless nodal fermion semimetal phase in ZrSiS, supported by first‑principles calculations, indicating that the ZrSiS family offers a platform for exotic quantum states and potential two‑dimensional topological insulators.

Abstract

Unveiling new topological phases of matter is one of the current objectives in condensed matter physics. Recent experimental discoveries of Dirac and Weyl semimetals prompt to search for other exotic phases of matter. Here we present a systematic angle-resolved photoemission spectroscopy (ARPES) study of ZrSiS, a prime topological nodal semimetal candidate. Our wider Brillouin zone (BZ) mapping shows multiple Fermi surface pockets such as the diamond-shaped Fermi surface, ellipsoidal-shaped Fermi surface, and a small electron pocket encircling at the zone center (G) point, the M point and the X point of the BZ, respectively. We experimentally establish the spinless nodal fermion semimetal phase in ZrSiS, which is supported by our first-principles calculations. Our findings evidence that the ZrSiS-type of material family is a new platform to explore exotic states of quantum matter, while these materials are expected to provide an avenue for engineering two-dimensional topological insulator systems.