Discovery of topological nodal-line fermionic phase in a magnetic material GdSbTe.

ABSTRACT: Topological Dirac semimetals with accidental band touching between conduction and valence bands protected by time reversal and inversion symmetry are at the frontier of modern condensed matter research. A majority of discovered topological semimetals are nonmagnetic and conserve time reversal symmetry. Here we report the experimental discovery of an antiferromagnetic topological nodal-line semimetallic state in GdSbTe using angle-resolved photoemission spectroscopy. Our systematic study reveals the detailed electronic structure of the paramagnetic state of antiferromagnetic GdSbTe. We observe the presence of multiple Fermi surface pockets including a diamond-shape, and small circular pockets around the zone center and high symmetry X points of the Brillouin zone (BZ), respectively. Furthermore, we observe the presence of a Dirac-like state at the X point of the BZ and the effect of magnetism along the nodal-line direction. Interestingly, our experimental data show a robust  Dirac-like state both below and above the magnetic transition temperature (T_N ?=?13?K). Having a relatively high transition temperature, GdSbTe provides an archetypical platform to study the interaction between magnetism and topological states of matter.

SUBMITTER: Hosen MM 

PROVIDER: S-EPMC6125290 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature