Visualizing the out-of-plane electronic dispersions in an intercalated transition metal dichalcogenide
Xiàn Yáng, Harrison LaBollita, Zi‐Jia Cheng, Hari Bhandari, Tyler A. Cochran, Jia‐Xin Yin, Md Shafayat Hossain, Ilya Belopolski, Qi Zhang, Yu-Xiao Jiang, Nana Shumiya, Daniel Multer, Maksim Liskevich, Д. А. Усанов, Yanliu Dang, Vladimir N. Strocov, Albert V. Davydov, N. Ghimire, Antía S. Botana, M. Zahid Hasan
Abstract
Layered transition metal dichalcogenides have a rich phase diagram and they feature two-dimensionality in numerous physical properties. ${\mathrm{Co}}_{1/3}{\mathrm{NbS}}_{2}$ is one of the newest members of this family where Co atoms are intercalated into the van der Waals gaps between ${\mathrm{NbS}}_{2}$ layers. We study the three-dimensional electronic band structure of ${\mathrm{Co}}_{1/3}{\mathrm{NbS}}_{2}$ 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, ${\mathrm{Co}}_{1/3}{\mathrm{NbS}}_{2}$ displays a different orbital character near the Fermi level compared to the pristine ${\mathrm{NbS}}_{2}$ compound and has a clear band dispersion in the ${k}_{z}$ direction despite its layered structure. Our photoemission study demonstrates the out-of-plane electronic correlations introduced by the Co intercalation, thus offering a different perspective on this compound. Finally, we propose how Fermi level tuning could lead to exotic phases such as spin density wave instability.