Work

High pressure induced superconductivity and chirality-neutral Fermi surface in SrS i 2

Year: 2024

Type: article

Abstract: In this study, we investigate the electronic structure and topological properties of the compound SrS i 2 using angle-resolved photoemission spectroscopy (ARPES), electrical transport measurements, and calculations. In contrast to recent theoretical predictions that SrS i 2 is a Weyl semimetal with robust Weyl nodes and Fermi arcs, our ARPES measurements on undoped and Ca-doped SrS i 2 single crystals show no evidence of the predicted Weyl fermions or Fermi arcs at ambient pressure. Instead, ARPES and transport data show that SrS i 2 is a narrow-gap semiconductor at ambient conditions. Our hybrid functional calculations also find a small band gap, in agreement with experiments. However, by applying external pressure, we induce a topological phase transition where the electronic bands overlap and Weyl nodes appear, as confirmed by transport measurements and calculations. Interestingly, we also observe a pressure-induced superconducting transition above 20 GPa. Our results establish SrS i 2 as a platform to study the interplay between topological states and superconductivity driven by external pressure. Importantly, our results challenge the previously predicted intrinsic Weyl semimetallic nature of SrS i 2 and highlight the need for combined experimental and advanced computational approaches to correctly describe the complex electronic structures in topological materials. Published by the American Physical Society 2024

Source: Physical review. B./Physical review. B

DOI: 10.1103/physrevb.110.224514