Non-trivial band topology and orbital-selective electronic nematicity in a new titanium-based kagome superconductor

Abstract

Electronic nematicity that spontaneously breaks rotational symmetry has been shown as a generic phenomenon in correlated quantum systems including high-temperature superconductors and the AV3Sb5 (A = K, Rb, Cs) family with a kagome network. Identifying the driving force has been a central challenge for understanding nematicity. In iron-based superconductors, the problem is complicated because the spin, orbital and lattice degrees of freedom are intimately coupled. In vanadium-based kagome superconductors AV3Sb5, the electronic nematicity exhibits an intriguing entanglement with the charge density wave order (CDW), making understanding its origin difficult. Recently, a new family of titanium-based kagome superconductors ATi3Bi5 has been synthesized. In sharp contrast to its vanadium-based counterpart, the electronic nematicity occurs in the absence of CDW. ATi3Bi5 provides a new window to explore the mechanism of electronic nematicity and its interplay with the orbital degree of freedom. Here, we combine polarization-dependent angle-resolved photoemission spectroscopy with density functional theory to directly reveal the band topology and orbital characters of the multi-orbital RbTi3Bi5. The promising coexistence of flat bands, type-II Dirac nodal line and nontrivial Z2 topological states is identified in RbTi3Bi5. Remarkably, our study clearly unveils the orbital character change along the G-M and G-K directions, implying a strong intrinsic inter-orbital coupling in the Ti-based kagome metals, reminiscent of iron-based superconductors. Furthermore, doping-dependent measurements directly uncover the orbital-selective features in the kagome bands, which can be well explained by the d-p hybridization. The suggested d-p hybridization, in collaboration with the inter-orbital coupling, could account for the electronic nematicity in ATi3Bi5.

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• Electronic nematicity without charge density waves in titanium-based kagome metal
• The kagomé metals RbTi${}_3$Bi${}_5$ and CsTi${}_3$Bi${}_5$
• Large kagome family candidates with topological superconductivity and charge density waves
• Screening promising CsV3Sb5-like kagome materials from systematic first-principles evaluation
• Titanium-based kagome superconductor CsTi_3Bi_5 and topological states

Cited by in corpus (24)

• Electronic Landscape of Kagome Superconductors $\text{A}$V${}_3$Sb${}_5$ ($\text{A}$ = K, Rb, Cs) from Angle-Resolved Photoemission Spectroscopy
• Superconducting, topological and transport properties of kagome metals CsTi${}_3$Bi${}_5$ and RbTi${}_3$Bi${}_5$
• Spin Excitations and Flat Electronic Bands in a Cr-based Kagome Superconductor
• Kagome metals
• Magnetic-coupled electronic landscape in bilayer-distorted titanium-based kagome metals
• Quantum Oscillations in kagome metals CsTi3Bi5 and RbTi3Bi5
• Revealing the orbital origins of exotic electronic states with Ti substitution in kagome superconductor CsV3Sb5
• Topological electronic structure and electronic nematicity in candidate kagome superconductors, ATi${}_3$Bi${}_5$ (A = Rb, Cs)
• Tuning electronic pairing by uniaxial strain in kagome lattices
• Flat bands and distinct density wave orders in correlated Kagome superconductor CsCr${}_3$Sb${}_5$
• Electronic structure of $A$V${}_3$Sb${}_5$ kagome metals
• Interplay of $d$- and $p$-states in RbTi${}_3$Bi${}_5$ and CsTi${}_3$Bi${}_5$ flat-band kagome metals
• High-order van Hove singularities and nematic instability in the kagome superconductor CsTi${}_3$Bi${}_5$
• Theories for charge-driven nematicity in kagome metals
• Common sublattice-pure van Hove singularities in the kagome superconductors $\text{A}$V${}_3$Sb${}_5$ ($\text{A}$ = K, Rb, Cs)
• Breathing-Driven Metal-Insulator Transition in Correlated Kagome Systems
• Odd-parity quadrupole order and induced nonreciprocal transport in the kagome metal CsTi${}_3$Bi${}_5$ driven by quantum interference
• Twisted Type-II Rashba Homobilayer: A Platform for Tunable Topological Flat Bands
• Nonequilibrium control of kagome metals
• Flat Band Generation through Interlayer Geometric Frustration in Intercalated Transition Metal Dichalcogenides
• Crystal structure, properties and pressure-induced insulator-metal transition in layered kagome chalcogenides
• Atomic-scale imaging of electronic nematicity in ferropnictides
• Superconductivity near an Ising nematic quantum critical point in two dimensions
• Effective Ionic Valence and Local Magnetic Moment in Kagome Superconductors