Surface vs bulk electronic structures of a moderately correlated topological insulator YbB6 revealed by ARPES
arXiv:1405.0165
Abstract
Systematic angle-resolved photoemission spectroscopy (ARPES) experiments have been carried out to investigate the bulk and (100) surface electronic structures of a topological mixed-valence insulator candidate, YbB6. The bulk states of YbB6 were probed with bulk-sensitive soft X-ray ARPES, which show strong three-dimensionality as required by cubic symmetry. Surprisingly the measured Yb 4f states are located around 1 eV and 2.3 eV below the Fermi level (EF), instead of being near EF as indicated by first principle calculations. The dispersive bands near EF are B 2p states, which hybridize with the 4f states. Using surface-sensitive vacuum-ultraviolet ARPES, we revealed two-dimensional surface states which form three electron-like Fermi surfaces (FSs) with Dirac-cone-like dispersions. The odd number of surface FSs gives the first indication that YbB6 is a moderately correlated topological insulator. The spin-resolved ARPES measurements provide further evidence that these surface states are spin polarized with spin locked to the crystal momentum. We have observed a second set of surface states with different topology (hole-like pockets). Clear folding of the bands suggest their origin from a 1X2 reconstructed surface. The topological property of the reconstructed surface states needs further studies.
arXiv comment5 figures
References in corpus (22)
- Topological Insulators
- Topological insulators and superconductors
- Mott physics and band topology in materials with strong spin-orbit interaction
- Topological Kondo Insulators
- Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
- Low-temperature surface conduction in the Kondo insulator SmB
- Correlated Topological Insulators with Mixed Valence
- 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
- A theory of Topological Kondo Insulators
- Surface and Bulk Electronic Structure of the Strongly Correlated System SmB and Implications for a Topological Kondo Insulator
- Topological Crystalline Kondo Insulator in Mixed Valence Ytterbium Borides
- Emergence of a coherent in-gap state in SmB6 Kondo insulator revealed by scanning tunneling spectroscopy
- Actinide Topological Insulator Materials with Strong Interaction
- Plutonium hexaboride is a correlated topological insulator
- The importance of Charge Fluctuations for the Topological Phase in SmB
- Weak Antilocalization and Linear Magnetoresistance in The Surface State of SmB6
- Bulk electronic structure of superconducting LaRu2P2 single crystals measured by soft x-ray angle-resolved photoemission spectroscopy
- End states in a 1-D topological Kondo insulator
- Temperature Dependence of Linked Gap and Surface State Evolution in the Mixed Valent Topological Insulator SmB6
- Imaging the Kondo Insulating Gap on SmB6