Direct measurement of a remnant Fermi surface in SmB6
arXiv:2111.07727
Abstract
The quest to understand the nature of the electronic state in SmB6 has been challenging, perplexing and surprising researchers for over half a century. In the theoretically predicted topological Kondo insulator SmB6, the nature of the bulk electronic structure is not characterised unambiguously by quantum oscillations due to contrary interpretations. One simple definition of an electrical insulator is a material that lacks a Fermi surface and here we report the results of our investigation into its existence in SmB6 by Compton scattering. Compton scattering measures occupied electron momentum states, is bulk sensitive due to the high energy of the incoming photons and is also an ultra-fast probe of the correlated many-body electron wavefunction. Remarkably, direct evidence for a three-dimensional remnant Fermi surface is observed. However, a further dichotomy is raised in that the full occupancy expected of a conventional metal is not reproduced. Our observation of a remnant Fermi surface using a momentum-resolved probe provides significant new evidence that the paradigm of a bulk insulator is not robust for SmB6.
arXiv comment14 pages, 10 figures (Supplementary information included)
References in corpus (20)
- Topological approach to Luttinger's theorem and the Fermi surface of a Kondo lattice
- Surface electronic structure of the topological Kondo insulator candidate correlated electron system SmB6
- Topological surface state in the Kondo Insulator Samarium Hexaboride
- Quantum oscillations in Kondo Insulator SmB
- 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
- Direct observation of the spin texture in strongly correlated SmB6 as evidence of the topological Kondo insulator
- Surface and Bulk Electronic Structure of the Strongly Correlated System SmB and Implications for a Topological Kondo Insulator
- Fermi surface in the absence of a Fermi liquid in the Kondo insulator SmB
- Kondo Breakdown and Quantum Oscillations in SmB
- Interaction Driven Subgap Spin Exciton in the Kondo Insulator SmB6
- Excitons in topological Kondo insulators - theory of thermodynamic and transport anomalies in SmB
- Anomalous 3D bulk AC conduction within the Kondo gap of SmB single crystals
- Large, high quality single-crystals of the new Topological Kondo Insulator, SmB6
- Pressure-resistant intermediate valence in Kondo insulator SmB6
- Majorana Fermi Sea in Insulating SmB6: A proposal and a Theory of Quantum Oscillations in Kondo Insulators
- Bulk and surface electronic properties of SmB6: a hard x-ray photoelectron spectroscopy study
- Low-temperature magnetic fluctuations in the Kondo insulator SmB6
- Suppression of magnetic excitations near the surface of the topological Kondo insulator SmB6
- Consistency of Photoemission and Quantum Oscillations for Surface States of SmB6