Interplay of $d$- and $p$-states in RbTi${}_3$Bi${}_5$ and CsTi${}_3$Bi${}_5$ flat-band kagome metals

Abstract

Shifting the Fermi level of the celebrated $A{M}_3{X}_5$ (135) compounds into proximity of flat bands strongly enhances electronic correlations and severely affects the formation of density waves and superconductivity. Our broadband infrared spectroscopy measurements of RbTi${}_3$Bi${}_5$ and CsTi${}_3$Bi${}_5$ combined with density-functional band-structure calculations reveal that the correlated Ti $d$-states are intricately coupled with the Bi $p$-states that form a tilted Dirac crossing. Electron-phonon coupling manifests itself in the strong damping of itinerant carriers and in the anomalous shape of the phonon line in RbTi${}_3$Bi${}_5$. An anomaly in these spectral features around 150 K can be paralleled to the onset of nematicity detected by low-temperature probes. Our findings show that the materials with low band filling open unexplored directions in the physics of kagome metals and involve electronic states of different nature strongly coupled with lattice dynamics.

References in corpus (32)

• Unconventional Fermi surface instabilities in the Kagome Hubbard Model
• Analysis of Charge Order in the Kagome Metal $A$V${}_3$Sb${}_5$ ($A=$K,Rb,Cs)
• Electronic instabilities of kagome metals: saddle points and Landau theory
• Kagome superconductors AV${}_3$Sb${}_5$ (A=K, Rb, Cs)
• AV${}_3$Sb${}_5$ Kagome Superconductors: Progress and Future Directions
• Use of X-ray scattering functions in Kramers-Kronig analysis of reflectance
• Superconductivity emerging from density-wave-like order in a correlated kagome metal
• Optical detection of charge-density-wave instability in the non-magnetic kagome metal KV${}_3$Sb${}_5$
• Low-energy optical properties of the non-magnetic kagome metal CsV${}_3$Sb${}_5$
• Observation of Flat Band, Dirac Nodal Lines and Topological Surface States in Kagome Superconductor CsTi${}_3$Bi${}_5$
• Electronic nematicity without charge density waves in titanium-based kagome metal
• Non-trivial band topology and orbital-selective electronic nematicity in a new titanium-based kagome superconductor
• Role of Sb in the superconducting kagome metal CsV${}_3$Sb${}_5$ revealed by its anisotropic compression
• Spin-reorientation-induced band gap in Fe${}_3$Sn${}_2$: Optical signatures of Weyl nodes
• Superconductivity and orbital-selective nematic order in a new titanium-based kagome metal CsTi3Bi5
• The kagomé metals RbTi${}_3$Bi${}_5$ and CsTi${}_3$Bi${}_5$
• Optical study of RbV${}_3$Sb${}_5$: Multiple density-wave gaps and phonon anomalies
• Large kagome family candidates with topological superconductivity and charge density waves
• Tunable van Hove singularity without structural instability in Kagome metal CsTi${}_3$Bi${}_5$
• Phenomenological model for charge dynamics and optical response of disordered systems: application to organic semiconductors
• Correlated Electronic Structure and Incipient Flat Bands of the Kagome Superconductor CsCr3Sb5
• Electronic properties of correlated kagomé metals AV${}_3$Sb${}_5$(A = K, Rb, Cs): A perspective
• Displaced Drude peak and bad metal from the interaction with slow fluctuations
• Universal sublinear resistivity in vanadium kagome materials hosting charge density waves
• The kagome Hubbard model from a functional renormalization group perspective
• Transient localization from the interaction with quantum bosons
• Effect of magnetism and phonons on localized carriers in the ferrimagnetic kagome metals GdMn${}_6$Sn${}_6$ and TbMn${}_6$Sn${}_6$
• Pressure evolution of electron dynamics in the superconducting kagome metal CsV${}_3$Sb${}_5$
• Quantum Oscillations in kagome metals CsTi3Bi5 and RbTi3Bi5
• Topological electronic structure and electronic nematicity in candidate kagome superconductors, ATi${}_3$Bi${}_5$ (A = Rb, Cs)
• The de Haas-van Alphen quantum oscillations in the kagome metal RbTi3Bi5
• Infrared spectroscopy study of kagome material CsTi${}_3$Bi${}_5$

Cited by in corpus (1)

• Kagome metals