A flat-band-induced ferromagnetic instability in the kagome metal Sc₃Mn₃Al₇Si₅

Kagome systems with rich electronic structures have become an intense research arena in the context of quantum spin liquids (QSL), charge density wave, and superconductivity. A Mn-based kagome system, Sc₃Mn₃Al₇Si₅, is proposed as an itinerant QSL via magnetic susceptibility and heat capacity measurements, and a possible ferromagnetic instability is reported with magnetization and nuclear magnetic resonance measurements [1,2]. To elucidate the ground state of this system, we conducted transport measurements of single crystals of Sc₃Mn₃Al₇Si₅ at low temperatures and high magnetic fields. The temperature dependence of resistivity at 0 T exhibits logarithmic divergence below 1 K. Magnetic fields suppress the logarithmic divergence and resistivity in high magnetic fields shows Fermi-liquid (FL) behavior. We find a scaling relation in magnetoresistance, suggesting that Sc₃Mn₃Al₇Si₅ is a ferromagnetic quantum critical metal due to flat-band-induced electron correlations and can be an exceptional example of interplay between electron correlation and topology of the underlying lattice. We will also discuss pseudogap-like behavior observed in soft-point-contact spectroscopy.



[1] H.He et al., Inorganic Chemistry 53,17 (2014)

[2] S.Samanta et al., arXiv:2304.04928