Visualizing the out-of-plane electronic dispersions in an intercalated transition metal dichalcogenide

TL;DR

This study reveals the three-dimensional electronic band structure of Co1/3NbS2, showing out-of-plane dispersions and altered orbital characters due to Co intercalation, challenging simple models and suggesting potential for exotic phases.

Contribution

It provides the first detailed experimental analysis of out-of-plane electronic dispersions in intercalated transition metal dichalcogenides, highlighting the effects of Co intercalation.

Findings

Electronic bands do not follow rigid-band-shift model.

Co intercalation introduces new orbital characters near the Fermi level.

Clear kz dispersion observed despite layered structure.

Abstract

Layered transition metal dichalcogenides have rich phase diagram and they feature two dimensionality on numerous physical properties. Co1/3NbS2 is one of the newest members of this family where Co atoms are intercalated into the Van der Waals gaps between NbS2 layers. We study the three-dimensional electronic band structure of Co1/3NbS2 using both surface and bulk sensitive angle-resolved photoemission spectroscopy. We show that the electronic bands do not fit into the rigid-band-shift picture after the Co intercalation. Instead, Co1/3NbS2 displays a different orbital character near the Fermi level compared to the pristine NbS2 compound and has a clear band dispersion in kz direction despite its layered structure. Our photoemission study demonstrates the out-of-plane electronic correlations introduced by the Co intercalation, thus offering a new perspective on this compound. Finally, we propose how Fermi level tuning could lead to exotic phases such as spin density wave instability.