Symmetry-selective quasiparticle scattering and electric field tunability of the ZrSiS surface electronic structure

Abstract

3D Dirac semimetals with square-net non-symmorphic symmetry, such as ternary ZrXY (X=Si, Ge; Y=S, Se, Te) compounds, have attracted significant attention owing to the presence of topological nodal lines, loops, or networks in their bulk. Orbital symmetry plays a profound role such materials as the different branches of the nodal dispersion can be distinguished by their distinct orbital symmetry eigenvalues. The presence of different eigenvalues suggests that scattering between states of different orbital symmetry may be strongly suppressed. Indeed, in ZrSiS, there has been no clear experimental evidence of quasiparticle scattering between states of different symmetry eigenvalue has been reported at small wave vector $q$. Here we show, using quasiparticle interference (QPI), that atomic step-edges in the ZrSiS surface facilitate quasiparticle scattering between states of different symmetry eigenvalues. This symmetry eigenvalue mixing quasiparticle scattering is the first to be reported for ZrSiS and contrasts quasiparticle scattering with no mixing of symmetry eigenvalues, where the latter occurs with scatterers preserving the glide mirror symmetry of the crystal lattice, e.g., native point defects in ZrSiS. Finally, we show that the electronic structure of the ZrSiS surface, including its unique floating band surface state (FBSS), can be tuned by a vertical electric field locally applied by the tip of a scanning tunneling microscope (STM), enabling control of a spin-orbit induced avoided crossing near the Fermi level by as much as 300%.

References in corpus (19)

• Topological Surface States Protected From Backscattering by Chiral Spin Texture
• Anomalous Hall Effect in Weyl Metals
• One-dimensional Topological Edge States of Bismuth Bilayers
• Photocurrents in Weyl semimetals
• Gate-Tunable Negative Longitudinal Magnetoresistance in the Predicted Type-II Weyl Semimetal WTe2
• Unexpected Dirac-Node Arc in the Topological Line-Node Semimetal HfSiS
• Dirac Line-nodes and Effect of Spin-orbit Coupling in Non-symmorphic Critical Semimetal MSiS (M=Hf, Zr)
• Nonlinear planar Hall effect
• Robust spin-polarized midgap states at step edges of topological crystalline insulators
• Emergent Electromagnetic Induction and Adiabatic Charge Pumping in Weyl Semimetals
• Surface floating 2D bands in layered nonsymmorphic semimetals: ZrSiS and related compounds
• Tunable large spin Hall and spin Nernst effects in Dirac semimetals ZrXY (X=Si, Ge; Y=S, Se, Te)
• Quasiparticle Interference Studies of Quantum Materials
• Observation of Effective Pseudospin Scattering in ZrSiS
• Evidence for bulk nodal loops and universality of Dirac-node arc surface states in ZrGeXc (Xc = S, Se, Te)
• Quasiparticle Interference in ZrSiS - Strongly Band-Selective Scattering Depending on Impurity Lattice Site
• Quasiparticle interference and quantum confinement in a correlated Rashba spin-split 2D electron liquid
• Anisotropic Berry phase in the Dirac nodal-line semimetal ZrSiS: The effect of spin-orbit coupling
• Unconventional magneto-resistance, and electronic transition in Mn${}_3$Ge Weyl semimetal