Kondo interaction in FeTe and its potential role in the magnetic order

TL;DR

This paper presents evidence of Kondo lattice behavior in FeTe, a d-electron antiferromagnetic metal, revealing hybridization between orbitals and potential interplay between Kondo effects and magnetic order.

Contribution

It provides the first spectroscopic evidence of d-electron Kondo lattice behavior in FeTe, linking hybridization and magnetic order.

Findings

Observation of a sharp quasiparticle at low temperatures

Confirmation of Fermi liquid behavior through transport measurements

Detection of hybridization gap via Fano spectra

Abstract

Finding d-electron heavy fermion (HF) states has been an important topic as the diversity in d-electron materials can lead to many exotic Kondo effect-related phenomena or new states of matter such as correlation-driven topological Kondo insulator or cooperation between long-range magnetism and Kondo lattice behavior. Yet, obtaining direct spectroscopic evidence for a d-electron HF system has been elusive to date. Here, we report the observation of Kondo lattice behavior in an antiferromagnetic metal, FeTe, via angle-resolved photoemission spectroscopy (ARPES) and transport properties measurements. The Kondo lattice behavior is represented by the emergence of a sharp quasiparticle at low temperatures. The transport property measurements confirm the low-temperature Fermi liquid behavior and reveal successive coherent-incoherent crossover upon increasing temperature. We interpret the Kondo lattice behavior as a result of hybridization between localized Fe 3dxy and itinerant Te 5pz orbitals. Our interpretation is further evidenced by Fano-type tunneling spectra which accompany a hybridization gap. Our observations strongly suggest unusual cooperation between Kondo lattice behavior and long-range magnetic order.