Imaging the Electronic Structures in Antiferromagnetic Dirac Semimetal GdSbTe

Dirac semimetals (DSMs) are characterized by topology- or symmetry- protected band crossings near the Fermi level that can form Dirac points, nodal lines, nodal surface or nodal chains in the electronic band structures. These unique band crossings can give rise to interesting properties such as large anisotropic magnetoresistance, chiral anomaly and flat optical conductivity. Moreover, magnetic DSMs can break the time reversal symmetry, where the interplay of symmetry, relativistic effects and the magnetic order can lead to novel quantum phases and offer the tunability of these quantum states with magnetic field. GdSbTe is a non-symmorphic semimetal with an antiferromagnetic phase below T=13K. By using spectroscopic imaging - scanning tunneling microscopy and first principle calculation, we investigated the surface and bulk electronic structures in GdSbTe across the magnetic transition and under magnetic field. Our quasiparticle scattering interference imaging and calculation showed the linear dispersion from Dirac bands over a wide energy range and are robust against different magnetic orders, suggesting the rigidity of the non-symmorphic crystalline symmetry protection in GdSbTe.