Revealing the Hidden Heavy Fermi Liquid in CaRuO3

Abstract

The perovskite ruthenate has attracted considerable interest due to reports of possible non-Fermi-liquid behavior and its proximity to a magnetic quantum critical point, yet its ground state and electronic structure remain enigmatic. Here we report the first measurements of the Fermi surface and quasiparticle dispersion in CaRuO3 through a combination of oxide molecular beam epitaxy and in situ angle-resolved photoemission spectroscopy. Our results reveal a complex and anisotropic Fermi surface consisting of small electron pockets and straight segments, consistent with the bulk orthorhombic crystal structure with large octahedral rotations. We observe a strongly band-dependent mass renormalization, with prominent heavy quasiparticle bands which lie close to the Fermi energy and exhibit strong temperature dependence. These results are consistent with a heavy Fermi liquid with a complex Fermiology and small hybridization gaps near the Fermi energy. Our results provide a unified framework for explaining previous experimental results on CaRuO3, such as its unusual optical conductivity, and demonstrate the importance of octahedral rotations in determining the quasiparticle band structure, and electron correlations in complex transition metal oxides.

arXiv comment4 figures

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Cited by in corpus (12)

• Hall coefficient signals orbital differentiation in the Hund's metal Sr${}_2$RuO${}_4$
• CaCu${}_3$Ru${}_4$O${}_{12}$: a high Kondo-temperature transition metal oxide
• Fermion condensation, $T$-linear resistivity and Planckian limit
• Separated transport relaxation scales and interband scattering in SrRuO${}_3$, CaRuO${}_3$, and Sr${}_2$RuO${}_4$ thin films
• Quasiparticle characteristics of the weakly ferromagnetic Hund's metal MnSi
• Strong terahertz third-harmonic generation by kinetic heavy quasiparticles in CaRuO${}_3$
• Orbital-selective metal skin induced by alkali-metal-dosing Mott-insulating Ca${}_2$RuO${}_4$
• Electronic band structure of (111) $SrRu{O}_3$ thin film$-$an angle-resolved photoemission spectroscopy study
• Orbitally-selective Breakdown of the Fermi Liquid and Simultaneous Enhancement of Metallic and Insulating States in Correlated Multi-band Systems with Spin-orbit Coupling
• Layer-dependent spin-resolved electronic structure of ferromagnetic triple-layered ruthenate Sr${}_4$Ru${}_3$O${}_{10}$
• Electronic and magnetic ground state of 4$d^3$ double perovskite ruthenates A${}_2$LaRuO${}_6$ (A $=$ Ca, Sr, Ba)
• Magic thickness of 25 Å makes periodic metal-insulator transitions