Abstract
Nonstoichiometric is known to exhibit a coexistence of magnetic order and the nontrivial semimetallic behavior. In this paper, we report the magnetism and its strong coupling to the semimetallic behavior, by a combined use of inelastic neutron scattering (INS) and density functional theory (DFT). A phase separation consisting of a majority antiferromagentic phase and a minority ferromagnetic phase is proposed. We found a relatively large spin excitation gap at 5 K, and the interlayer magnetic exchange constant only 2.8% of the dominant intralayer magnetic interaction, evidencing a quasi-2D magnetism in . Using DFT, we find a strong influence of magnetic orders on the electronic band structure and the Dirac dispersions near the Fermi level along the Y-S direction in the presence of a ferromagnetic order. Furthermore, we demonstrate that the size of the ferromagnetic ordered moment is an effective strategy to tune Dirac/Weyl dispersions near the Fermi level. Our study unveils novel interplay between the magnetic order, ordered moment, and electronic band topology in and opens pathways to control the relativistic band structure.
- Received 6 January 2019
- Revised 15 October 2019
DOI:https://doi.org/10.1103/PhysRevB.100.205105
©2019 American Physical Society