Consistency between ARPES and STM measurements on SmB${}_6$

Abstract

Strongly correlated topological surface states are promising platforms for next-generation quantum applications, but they remain elusive in real materials. The correlated Kondo insulator SmB${}_6$ is one of the most promising candidates, with theoretically predicted heavy Dirac surface states supported by transport and scanning tunneling microscopy (STM) experiments. However, a puzzling discrepancy appears between STM and angle-resolved photoemission (ARPES) experiments on SmB${}_6$. Although ARPES detects spin-textured surface states, their velocity is an order of magnitude higher than expected, while the Dirac point -- the hallmark of any topological system -- can only be inferred deep within the bulk valence band. A significant challenge is that SmB${}_6$ lacks a natural cleavage plane, resulting in ordered surface domains limited to 10s of nanometers. Here we use STM to show that surface band bending can shift energy features by 10s of meV between domains. Starting from our STM spectra, we simulate the full spectral function as an average over multiple domains with different surface potentials. Our simulation shows excellent agreement with ARPES data, and thus resolves the apparent discrepancy between large-area measurements that average over multiple band-shifted domains and atomically-resolved measurements within a single domain.

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• Imaging emergent heavy Dirac fermions of a topological Kondo insulator
• Observation of perfect Andreev reflection due to Klein paradox in a topological superconducting state
• Visualizing the atomic-scale origin of metallic behavior in Kondo insulators
• Definitive Surface Magnetotransport Study of SmB${}_6$
• Direct comparison of ARPES, STM, and quantum oscillation data for band structure determination in Sr${}_2$RhO${}_4$
• Robust surface states and coherence phenomena in magnetically alloyed SmB6
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Transition to an excitonic insulator from a two-dimensional conventional insulator
• Phase stability in SmB${}_6$
• Surface excitations relaxation in the Kondo insulator Sm${}_{1-x}$Gd${}_x$B${}_6$
• Observation of the superconducting proximity effect from surface states in SmB${}_6$/YB${}_6$ thin film heterostructures via terahertz spectroscopy
• Nanoscale Conducting and Insulating Domains on YbB${}_6$