Pomeranchuk instability from electronic correlations in CsTi3Bi5 kagome metal
- Chiara Bigi
- Matteo Dürrnagel
- Lennart Klebl
- Armando Consiglio
- Ganesh Pokharel
- Marta Zonno
- François Bertran
- Patrick Le Fèvre
- Thomas Jaouen
- Hulerich C. Tchouekem
- Pascal Turban
- Alessandro De Vita
- Jill A. Miwa
- Justin W. Wells
- Dongjin Oh
- Riccardo Comin
- Ronny Thomale
- Ilija Zeljkovic
- Brenden R. Ortiz
- Stephen D. Wilson
- Giorgio Sangiovanni
- Federico Mazzola
- Domenico Di Sante
2025-12-23
Electronic nematicity, the spontaneous breaking of rotational symmetry, has emerged as a key instability in correlated quantum systems. CsTi 3 Bi 5 , a kagome metal of the AV 3 Sb 5 (A = K, Rb, Cs) family, hosts rich unconventional electronic phases, yet the origin of its nematicity remains unsettled. Here, we combine polarization-dependent angle-resolved photoemission spectroscopy with functional renormalization group calculations on a fully interacting ab initio model. We reveal an orbital-selective nematic deformation in the low-energy band structure and identify a finite angular momentum ( d -wave) Pomeranchuk instability driven by electronic correlations in specific orbital channels and detuning from Van Hove singularities. Our results establish a direct link between orbital selectivity and symmetry-breaking instabilities in CsTi 3 Bi 5 , providing a microscopic framework for nematic order in kagome systems.