Abstract Body

Exploring exotic electronic orders and their underlying driving forces remains a central pursuit in the field of quantum materials. Within this context, the kagome lattice, a corner-sharing triangle network, has emerged as a versatile platform for exploring unconventional correlated and topological quantum states. Due to the unique correlation effects and frustrated lattice geometry inherent to kagome lattices, several families of kagome metals have been found to display a variety of competing electronic instabilities and nontrivial topologies, including quantum spin liquid, unconventional superconductivity, charge density wave orders, and Dirac/Weyl semimetals. Against this backdrop, kagome systems offer an exceptional quantum playground for delving into the intricate interplay among electron correlation effects, geometric frustration, and band topology. In this talk, I will present our recent work, focusing specifically on the unconventional electronic instabilities observed in kagome superconductors AV₃Sb₅ (A = K, Rb, Cs) [1-5] and ATi₃Bi₅ [6,7]. Drawing particularly from the insights derived from angle-resolved photoemission spectroscopy (ARPES), I will highlight the unique characteristics of these systems, shedding light on their intriguing electronic behaviors and elucidating their underlying mechanisms.

References

[1] B. R. Ortiz et al. Phys. Rev. Lett. 125, 247002 (2020).

[2] Y. Hu et al. Nat. Commun. 13, 2220 (2022).

[3] Y. Hu et al. Sci. Bull. 67(5):495–500 (2022).

[4] Y. Hu et al. Phys. Rev. B 106, L241106 (2022). Editors’ suggestion

[5] Y. Hu et al. npj Quant. Mater. 8, 67 (2023).(Invited Review)

[6] Y. Hu et al. Nat. Phys. 19, 1827–1833 (2023).

[7] Y. Hu et al. Supercond. Sci. Technol. (2024). (Invited review)

Figure 1. a Kagome lattice. b Tight-binding band structure of kagome lattice featuring Dirac cone (DC), flat band, and van Hove singularity (VHS), as indicated by red arrow.c Novel electronic states found in kagome superconductors AV₃Sb₅ (i) and ATi₃Bi₅ (ii).

Keywords: Kagome Superconductors, Charge Order, Electronic Nematicity, ARPES