Kondo holes in the 2D itinerant Ising ferromagnet Fe3GeTe2

TL;DR

This paper reports the discovery of enhanced Kondo screening at vacancies in Fe3GeTe2, a 3d-electron system exhibiting heavy fermion behavior and 2D ferromagnetism, revealing the interplay between magnetism and Kondo effects.

Contribution

It introduces an itinerant Kondo-Ising model that explains the microscopic origin of heavy fermion states in a 3d ferromagnet with Kondo holes.

Findings

Enhanced Kondo screening observed at Fe vacancies.

Theoretical model reproduces experimental results.

Insights into competition between ferromagnetism and Kondo screening.

Abstract

Heavy fermion (HF) states emerge in correlated quantum materials due to the interplay between localized magnetic moments and itinerant electrons, but rarely appear in 3d-electron systems due to high itinerancy of d-electrons. Here, an anomalous enhancement of Kondo screening is observed at the Kondo hole of local Fe vacancies in Fe3GeTe2 which is a recently discovered 3d-HF system featuring of Kondo lattice and two-dimensional itinerant ferromagnetism. An itinerant Kondo-Ising model is established to reproduce the experimental results which provides insight of the competition between Ising ferromagnetism and Kondo screening. This work explains the microscopic origin of the d-electron HF states and inspires study of the enriched quantum many-body phenomena with Kondo holes in Ising ferromagnets.