Mechanism of magnetic phase transition in correlated magnetic metal: insight into itinerant ferromagnet Fe${}_{3-\delta }$GeTe${}_2$

Abstract

Developing a comprehensive magnetic theory for correlated itinerant magnets poses challenges due to the difficulty in reconciling both local moments and itinerant electrons. In this work, we investigate the microscopic process of magnetic phase transition in ferromagnetic metal Fe${}_{3-\delta }$GeTe${}_2$. We find that Hund's coupling is crucial for establishing ferromagnetic order. During the ferromagnetic transition, we observe the formation of quasiparticle flat bands and an opposing tendency in spectral weight transfer, primarily between the lower and upper Hubbard bands, across the two spin channels. Moreover, our results indicate that one of the inequivalent Fe sites exhibits Mott physics, while the other Fe site exhibits Hund's physics, attributable to their distinct atomic environments. We suggest that ferromagnetic order reduces spin fluctuations and makes flat bands near the Fermi level more distinct. The hybridization between the distinctly flat bands and other itinerant bands offers a possible way to form heavy fermion behavior in ferromagnets. The complex interactions of competing orders drive correlated magnetic metals to a new frontier for discovering outstanding quantum states.

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Cited by in corpus (6)

• DFT+DMFT investigation of the magnetic phase transition in the itinerant ferromagnet Fe${}_3$GaTe${}_2$
• The electronic structures, magnetic transition and Fermi surface instability of room-temperature altermagnet KV${}_2$Se${}_2$O
• Electronic structures and magnetism in van der Waals flat-band material Ni${}_3$GeTe${}_2$
• Robustness of ferromagnetism in van der Waals magnet Fe${}_3$GeTe${}_2$ to hydrostatic pressure
• Local magnetic structure in fully and partially ordered V${}_2$$X$Al Heusler alloys ($X$=Cr, Mn, Fe, Co, Ni)
• Signatures of Kondo-lattice behavior in the two-dimensional ferromagnet Fe${}_3$GeTe${}_2$