Anomalous 4$f$ fine structure in TmSe${}_{1-x}$Te${}_x$ across the metal-insulator transition

Abstract

Hybridization between localized 4$f$ and itinerant 5$d$6$s$ states in heavy fermion compounds is a well-studied phenomenon and commonly captured by the paradigmatic Anderson model. However, the investigation of additional electronic interactions, beyond the standard Anderson model, has been limited, despite their predicted important role in the exotic quasiparticle formation in mixed-valence systems. We investigate the 4$f$ states in TmSe${}_{1-x}$Te${}_x$ throughout a semimetal-insulator phase transition, which drastically varies the interactions related to the 4$f$ states. Using synchrotron-based hard x-ray and extreme ultraviolet photoemission spectroscopy, we resolve subtle peak splitting in the 4$f$ peaks near the Fermi level in the mixed-valent semimetal phase. The separation is enhanced by several tens of meV by increasing the lattice parameter by a few percent. Our results elucidate the evolving nature of the 4$f$ state across the phase transition, and provide direct experimental evidence for electronic interactions beyond the standard Anderson model in mixed-valence systems.

arXiv comment5 pages, 4 figures for the main text, 6 pages and 5 figures for the supplementary

References in corpus (30)

• Topological Kondo Insulators
• Multiplet ligand-field theory using Wannier orbitals
• Quantum oscillations in Kondo Insulator SmB${}_6$
• Tunable polaronic conduction in anatase TiO2
• Unconventional Fermi surface in an insulating state
• Efficient real frequency solver for dynamical mean field theory
• Origin of the crossover from polarons to Fermi liquids in transition metal oxides
• On the possibility of an excitonic insulator at the semiconductor-semimetal transition
• Quantum Oscillations of Electrical Resistivity in an Insulator
• Fermi surface in the absence of a Fermi liquid in the Kondo insulator SmB${}_6$
• Excitons in topological Kondo insulators - theory of thermodynamic and transport anomalies in SmB${}_6$
• Multipolar phases and magnetically hidden order: Review of the heavy-fermion compound Ce(1-x)La(x)B6
• Electron-phonon interaction and antiferromagnetic correlations
• Additional energy scale in SmB${}_6$ at low temperature
• Anomalous 3D bulk AC conduction within the Kondo gap of SmB${}_6$ single crystals
• Valence and magnetic ordering in intermediate valence compounds : TmSe versus SmB6
• Bulk Fermi surface of charge-neutral excitations in SmB6 or not: a heat-transport study
• Unusual high-field metal in a Kondo insulator
• Majoranas in mixed-valence insulators
• Bulk and surface electronic properties of SmB6: a hard x-ray photoelectron spectroscopy study
• Topological properties and the dynamical crossover from mixed-valence to Kondo-lattice behavior in golden phase of SmS
• Yb Valence Change in (Ce,Yb)CoIn5 from spectroscopy and bulk properties
• Valence Characterization of Surface and Subsurface Region in SmB6
• SmO thin films: a flexible route to correlated flat bands with nontrivial topology
• Valence effect on the thermopower of Eu systems
• Hybridization and Correlation between f- and d-orbital electrons in a valence fluctuating compound EuNi2P2
• Universal properties of the near-gap spectra of SmB6: dynamical mean-field calculations and photoemission experiments
• Mixed-valence state in the dilute-impurity regime of La-substituted SmB${}_6$
• Mobility gap in intermediate valent TmSe
• Studies on X-ray Thomson Scattering from Antiferroquadrupolar Order in TmTe