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arXiv · 2208.12456

Quasiparticle characteristics of the weakly ferromagnetic Hund's metal MnSi

Yuan Fang·Huali Zhang·Ding Wang·Guowei Yang·Yi Wu·Peng Li·Zhiguang Xiao·Tianyun Lin·Hao Zheng·Xiao-Long Li·Huan-Hua Wang·Fanny Rodolakis·Yu Song·Yilin Wang·Chao Cao·Yang Liu
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Abstract

Hund's metals are multi-orbital systems with $3d$ or $4d$ electrons exhibiting both itinerant character and local moments, and they feature Kondo-like screenings of local orbital and spin moments, with suppressed coherence temperature driven by Hund's coupling $J_H$. They often exhibit magnetic order at low temperature, but how the interaction between the Kondo-like screening and long-range magnetic order is manifested in the quasiparticle spectrum remains an open question. Here we present spectroscopic signature of such interaction in a Hund's metal candidate MnSi exhibiting weak ferromagnetism. Our photoemission measurements reveal renormalized quasiparticle bands near the Fermi level with strong momentum dependence: the ferromagnetism manifests through possibly exchange-split bands (Q1) below $T_C$ , while the spin/orbital screenings lead to gradual development of quasiparticles (Q2) upon cooling. Our results demonstrate how the characteristic spin/orbital coherence in a Hund's metal could coexist and compete with the magnetic order to form a weak itinerant ferromagnet, via quasiparticle bands that are well separated in momentum space and exhibit distinct temperature dependence. Our results imply that the competition between the spin/orbital screening and the magnetic order in a Hund's metal bears intriguing similarity to the Kondo lattice systems.

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Yuan Fang, Huali Zhang, Ding Wang, Guowei Yang, Yi Wu, Peng Li, Zhiguang Xiao, Tianyun Lin, Hao Zheng, Xiao-Long Li, Huan-Hua Wang, Fanny Rodolakis, Yu Song, Yilin Wang, Chao Cao, Yang Liu. 2022-10-14. Quasiparticle characteristics of the weakly ferromagnetic Hund's metal MnSi. https://doi.org/10.1103/physrevb.106.l161112

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