Surface properties of SmB6 from x-ray photoelectron spectroscopy

Abstract

We have investigated the properties of cleaved SmB${}_6$ single crystals by x-ray photoelectron spectroscopy. At low temperatures and freshly cleaved samples a surface core level shift is observed which vanishes when the temperature is increased. A Sm valence between 2.5 - 2.6 is derived from the relative intensities of the Sm${}^{2+}$ and Sm${}^{3+}$ multiplets. The B/Sm intensity ratio obtained from the core levels is always larger than the stoichiometric value. Possible reasons for this deviation are discussed. The B $1s$ signal shows an unexpected complexity: an anomalous low energy component appears with increasing temperature and is assigned to the formation of a suboxide at the surface. While several interesting intrinsic and extrinsic properties of the SmB${}_6$ surface are elucidated in this manuscript no clear indication of a trivial mechanism for the prominent surface conductivity is found.

References in corpus (14)

• 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${}_6$
• 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${}_6$ and Implications for a Topological Kondo Insulator
• 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
• Momentum-Dependent Hybridization Gap and dispersive in-gap state of The Kondo Semiconductor SmB6
• Kondo hybridisation and the origin of metallic states at the (001) surface of SmB6
• Resonant magnetic exciton mode in the heavy-fermion antiferromagnet CeB6
• The importance of Charge Fluctuations for the Topological Phase in SmB${}_6$

Cited by in corpus (4)

• Surface-state spin textures and mirror Chern numbers in topological Kondo insulators
• Pressure-resistant intermediate valence in Kondo insulator SmB6
• Chemical and valence reconstruction at the surface of SmB6 revealed with resonant soft x-ray reflectometry
• Valence Characterization of Surface and Subsurface Region in SmB6