Experimental observation of bulk nodal lines and electronic surface states in ZrB${}_2$

Abstract

Topological nodal-line semimetals are characterized by the line-contact bulk band crossings and the topological surface states. Breaking certain protecting symmetry turns this system into a Dirac semimetal or Weyl semimetal that hosts zero-dimensional isolated nodal points. Recent advances in band theory predicted a topological nodal-line semimetal state possessing a new type of nodal line in AlB${}_2$-type diborides. Here, we report an experimental realization of nodal-line fermions and associated surface states near the Fermi energy in ZrB${}_2$ by angle-resolved photoemission spectroscopy combined with first-principles calculations. The Dirac nodal lines in ZrB${}_2$ wind into two groups of nodal rings, which are linked together along the $\Gamma$-$K$ direction. We further observe a distinct surface state connecting to each nodal line, indicative of the nontrivial topological nature of the bulk nodal lines. Therefore, our results provide convincing experimental evidence of the nodal-line semimetal states in ZrB${}_2$ both in the bulk and on the surface, suggesting ZrB${}_2$ as a remarkable platform for discovering unique phenomena induced by nodal-line fermions.

arXiv comment24 pages, 4 figures

References in corpus (31)

• Topological Insulators
• Topological insulators and superconductors
• Electronic Structure of Pyrochlore Iridates: From Topological Dirac Metal to Mott Insulator
• Discovery of a Weyl Fermion Semimetal and Topological Fermi Arcs
• Type-II Weyl Semimetals
• Discovery of a Three-dimensional Topological Dirac Semimetal, Na3Bi
• Maximally-localized Wannier functions for entangled energy bands
• Dirac semimetal and topological phase transitions in A3Bi (A=Na, K, Rb)
• Topological nodal semimetals
• Theoretical Discovery/Prediction: Weyl Semimetal states in the TaAs material (TaAs, NbAs, NbP, TaP) class
• Experimental Realization of a Three-Dimensional Dirac Semimetal
• Observation of Weyl nodes in TaAs
• Anomalous Hall Effect and Magnetic Monopoles in Momentum-Space
• Dirac Cone Protected by Non-Symmorphic Symmetry and 3D Dirac Line Node in ZrSiS
• Topological Node-Line Semimetal in Three Dimensional Graphene Networks
• Topological nodal line semimetals
• Topological Origin of Zero-Energy Edge States in Particle-Hole Symmetric Systems
• Topological nodal-line fermions in ZrSiSe and ZrSiTe
• Topological Semimetals Predicted from First-principles Calculations
• Dirac node lines in pure alkali earth metals
• Unexpected Dirac-Node Arc in the Topological Line-Node Semimetal HfSiS
• Nearly massless Dirac fermions and strong Zeeman splitting in the nodal-line semimetal ZrSiS probed by de Haas--van Alphen quantum oscillations
• Tunability of the topological nodal-line semimetal phase in ZrSiX-type materials
• Coexistence of four-band nodal rings and triply-degenerate nodal points in centrosymmetric metal diborides
• Surface dominated transport in single crystalline nanoflake devices of topological insulator Bi1.5Sb0.5Te1.8Se1.2
• Topological Dirac Nodal-net Fermions in AlB${}_2$-type TiB${}_2$ and ZrB${}_2$
• Exploration and prediction of topological electronic materials based on first-principles calculations
• Topological surface electronic states in candidate nodal-line semimetal CaAgAs
• Emergence of topological bands on the surface of ZrSnTe crystal
• Experimental Observation of Dirac Nodal Links in Centrosymmetric Semimetal TiB${}_2$
• Extremely large magnetoresistance and high-density Dirac-like fermions in ZrB2

Cited by in corpus (26)

• Topological Materials Discovery from Crystal Symmetry
• Jones polynomial and knot transitions in topological semimetals
• Observation of nodal-line semimetal with ultracold fermions in an optical lattice
• Observation of non-Abelian nodal links in photonics
• Superconducting and Topological Properties in Centrosymmetric PbTaS2 Single Crystals
• Disorder driven multifractality transition in Weyl nodal loops
• Hyperbolic Nodal Band Structures and Knot Invariants
• Evidence of topological nodal lines and surface states in the centrosymmetric superconductor SnTaS2
• Signature of weakly coupled $f$ electrons and conduction electrons in magnetic Weyl semimetal candidates PrAlSi and SmAlSi
• Topological semimetallic phase in PbO${}_2$ promoted by temperature
• Magnetotransport Properties and Fermi Surface Topology of Nodal line Semimetal InBi
• Superconductivity and a van Hove singularity confined to the surface of a topological semimetal
• Electronic structure and open-orbit Fermi surface topology in isostructural semimetals NbAs${}_2$ and W${}_2$As${}_3$ with extremely large magnetoresistance
• Broken-symmetry phases of interacting nested Weyl and Dirac loops
• Fractal Nodal Band Structures
• Observation of a flat and extended surface state in a topological semimetal
• Tunable Charged Domain Wall from Topological Confinement in Nodal-Line Semimetals
• Crossing points of nodal lines in topological semimetals and Fermi surface of ZrSiS
• Delocalization of topological surface states by diagonal disorder in nodal loop semimetals
• Ultrafast relaxation of acoustic and optical phonons in a topological nodal-line semimetal ZrSiS
• Exploration of Altermagnetism in $\mathrm{Ru}{\mathrm{O}}_2$
• Unconventional Topological Insulators from Extended Topological Band Degeneracies
• Emergent topology in thin films of nodal line semimetals
• Accelerated Discovery of Topological Conductors for Nanoscale Interconnects
• Breakdown of chiral anomaly and emergent phases in Weyl semimetals under orbital magnetic fields
• Magnetic susceptibility of crystals with crossing of their band-contact lines