Comparative study of rare earth hexaborides using high resolution angle-resolved photoemission

Abstract

Strong electron correlations in rare earth hexaborides can give rise to a variety of interesting phenomena like ferromagnetism, Kondo hybridization, mixed valence, superconductivity and possibly topological characteristics. The theoretical prediction of topological properties in SmB${}_6$ and YbB${}_6$, has rekindled the scientific interest in the rare earth hexaborides, and high-resolution ARPES has been playing a major role in the debate. The electronic band structure of the hexaborides contains the key to understand the origin of the different phenomena observed, and much can be learned by comparing the experimental data from different rare earth hexaborides. We have performed high-resolution ARPES on the (001) surfaces of YbB${}_6$, CeB${}_6$ and SmB${}_6$. On the most basic level, the data show that the differences in the valence of the rare earth element are reflected in the experimental electronic band structure primarily as a rigid shift of the energy position of the metal 5$\text{d}$ states with respect to the Fermi level. Although the overall shape of the $\text{d}$-derived Fermi surface contours remains the same, we report differences in the dimensionality of these states between the compounds studied. Moreover, the spectroscopic fingerprint of the 4$\text{f}$ states also reveals considerable differences that are related to their coherence and the strength of the $\text{d}$-$\text{f}$ hybridization. For the SmB${}_6$ case, we use ARPES in combination with STM imaging and electron diffraction to reveal time dependent changes in the structural symmetry of the highly debated SmB${}_6$(001) surface. All in all, our study highlights the suitability of electron spectroscopies like high-resolution ARPES to provide links between electronic structure and function in complex and correlated materials such as the rare earth hexaborides.

10 pages, 5 figures

References in corpus (15)

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• Correlated Topological Insulators with Mixed Valence
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• Tuning bulk and surface conduction in topological Kondo insulator SmB6
• Kondo Breakdown in Topological Kondo Insulators
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• A band structure scenario for the giant spin-orbit splitting observed at the Bi/Si(111) interface
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• Dirac states with knobs on: interplay of external parameters and the surface electronic properties of 3D topological insulators
• Suppression of dense Kondo state in CeB6 under pressure
• ARPES insights on the metallic states of YbB6(001): E(k) dispersion, temporal changes and spatial variation
• Micro-metric electronic patterning of a topological band structure using a photon beam

Cited by in corpus (11)

• Additional energy scale in SmB${}_6$ at low temperature
• Consistency between ARPES and STM measurements on SmB${}_6$
• Derivation of RKKY Interaction between Multipole Moments in CeB${}_6$ by the Effective Wannier Model based on the Bandstructure Calculation
• Bulk Electronic Structure of Lanthanum Hexaboride (LaB6) by Hard X-ray Angle-Resolved Photoelectron Spectroscopy
• Surface resonance of the (2$\times$1) reconstructed lanthanum hexaboride (001)-cleavage plane: a combined STM and DFT study
• Robust surface states and coherence phenomena in magnetically alloyed SmB6
• An STM perspective on hexaborides: Surface states of the Kondo insulator SmB${}_6$
• Comparative Scanning Tunneling Microscopy Study on Hexaborides
• Exploring itinerant states in divalent hexaborides using rare-earth $L$ edge resonant inelastic X-ray scattering
• RKKY interactions of CeB6 based on effective Wannier model
• Nanoscale Conducting and Insulating Domains on YbB${}_6$