Disentangle Intertwined Interactions in Correlated Charge Density Wave with Magnetic Impurities

TL;DR

This study investigates how magnetic impurities interact with charge density waves in a correlated material, revealing site-specific behaviors and hybridization effects that challenge existing models and suggest new control mechanisms.

Contribution

It uncovers the microscopic mechanisms of site-dependent interactions between Fe adatoms and a cluster-Mott CDW system using STM/STS and DFT, highlighting hybridization and charge transfer effects.

Findings

Site-dependent electronic states of Fe adatoms on CDW clusters

Hybridization with localized electrons suppresses Mott insulating state

Limitations of single-site Kondo impurity model in this context

Abstract

Magnetic impurities in strongly correlated electronic systems serve as sensitive probes to a wide range of many-body quantum phenomena. Broken symmetries in such a system can lead to inequivalent lattice sites, and magnetic impurities may interact selectively with particular orbitals or sublattices. However, the microscopic mechanisms behind such site-specific interactions have been poorly understood. Here, we explore the behavior of individual Fe adatoms on a cluster-Mott charge-density-wave (CDW) system of 1T-TaS2 utilizing scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT). Our measurements uncover pronounced site-dependent electronic states of CDW clusters with Fe adatoms, indicating distinct local coupling to cluster-Mott states. DFT calculations identify three distinct types of interactions; hybridization with localized correlated electrons, distorting the CDW cluster, and charge transfer. In particular, the hybridization of Fe 3d and half-filled Ta 5dz2 orbitals suppresses the Mott insulating state for an adatom at the center of a CDW cluster. While the results underscore a crucial role of the direct orbital hybridization and the limitation of the prevailing single-site Kondo impurity model, they suggest the possibility of controlling entangled interactions separately in a cluster Mott insulator.