ARPES insights on the metallic states of YbB6(001): E(k) dispersion, temporal changes and spatial variation

Abstract

We report high resolution Angle Resolved PhotoElectron Spectroscopy (ARPES) results on the (001) cleavage surface of YbB${}_6$, a rare-earth compound which has been recently predicted to host surface electronic states with topological character. We observe two types of well-resolved metallic states, whose Fermi contours encircle the time-reversal invariant momenta of the YbB${}_6$(001) surface Brillouin zone, and whose full (E,$k$)-dispersion relation can be measured wholly unmasked by states from the rest of the electronic structure. Although the two-dimensional character of these metallic states is confirmed by their lack of out-of-plane dispersion, two new aspects are revealed in these experiments. Firstly, these states do not resemble two branches of opposite, linear velocity that cross at a Dirac point, but rather straightforward parabolas which terminate to high binding energy with a clear band bottom. Secondly, these states are sensitive to time-dependent changes of the YbB${}_6$ surface under ultrahigh vacuum conditions. Adding the fact that these data from cleaved YbB${}_6$ surfaces also display spatial variations in the electronic structure, it appears there is little in common between the theoretical expectations for an idealized YbB${}_6$(001) crystal truncation on the one hand, and these ARPES data from real cleavage surfaces on the other.

arXiv comment8 pages, 4 figures (accepted in Physical Review B)

References in corpus (34)

• Topological Insulators
• Topological insulators and superconductors
• Mott physics and band topology in materials with strong spin-orbit interaction
• Topological Surface States Protected From Backscattering by Chiral Spin Texture
• Topological Kondo Insulators
• Experimental demonstration of the topological surface states protected by the time-reversal symmetry
• Unveiling a two-dimensional electron gas with universal subbands at the surface of SrTiO3
• Fractional quantum Hall effect in the absence of Landau levels
• Fractional Chern Insulator
• STM imaging of electronic waves on the surface of Bi${}_2$Te${}_3$: topologically protected surface states and hexagonal warping effects
• Creation and control of a two-dimensional electron liquid at the bare SrTiO3 surface
• Large tuneable Rashba spin splitting of a two-dimensional electron gas in Bi2Se3
• Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
• Low-temperature surface conduction in the Kondo insulator SmB${}_6$
• Correlated Topological Insulators with Mixed Valence
• Spatial Fluctuations of Helical Dirac Fermions on the Surface of Topological Insulators
• Topological surface state in the Kondo Insulator Samarium Hexaboride
• Robust Surface Hall Effect and Nonlocal Transport in SmB6: Indication for an Ideal Topological Insulator
• Observation of in-gap surface states in the Kondo insulator SmB6 by photoemission
• Surface and Bulk Electronic Structure of the Strongly Correlated System SmB${}_6$ and Implications for a Topological Kondo Insulator
• Cubic Topological Kondo Insulators
• Topological Crystalline Kondo Insulator in Mixed Valence Ytterbium Borides
• Hybridization, Inter-Ion Correlation, and Surface States in the Kondo Insulator SmB6
• Excitonic ferromagnetism in the hexaborides
• Polarity-driven surface metallicity in SmB${}_6$
• Hybridization gap and Fano resonance in SmB${}_6$
• Emergence of a coherent in-gap state in SmB6 Kondo insulator revealed by scanning tunneling spectroscopy
• Bulk Band Gaps in Divalent Hexaborides
• Ferromagnetism and superstructure in Ca_{1-x}La_xB_6
• Kondo hybridisation and the origin of metallic states at the (001) surface of SmB6
• The importance of Charge Fluctuations for the Topological Phase in SmB${}_6$
• Electron self-trapping in intermediate-valent SmB6
• Angle-resolved Photoemission Spectroscopy Study on the Surface States of the Correlated Topological Insulator YbB6
• Theory of Excitonic States in CaB6

Cited by in corpus (6)

• Samarium hexaboride: A trivial surface conductor
• Electronic structure of YbB${}_6$: Is it a Topological Insulator or not?
• Pressure-induced quantum phase transitions in topological insulator YbB6
• Electronic structure of the candidate 2D Dirac semimetal SrMnSb2: a combined experimental and theoretical study
• Comparative study of rare earth hexaborides using high resolution angle-resolved photoemission
• Nanoscale Conducting and Insulating Domains on YbB${}_6$