Strongly correlated topological surface states in type-II Dirac semimetal NiTe$_{2}$

TL;DR

This study investigates the topological surface states in NiTe$_{2}$, revealing that strong surface electronic correlations are essential to accurately describe the Dirac-like states, which has implications for future electronic and spintronic applications.

Contribution

The paper demonstrates that incorporating surface electronic correlation is crucial for accurately modeling topological surface states in NiTe$_{2}$, bridging the gap between theory and experiment.

Findings

Strongly correlated surface states form Dirac-like crossings below Fermi level.

Surface electronic correlation significantly influences topological surface states.

Hybridization of Ni 3d and Te 5p orbitals underpins the observed phenomena.

Abstract

Nontrivial topology in type-II Dirac semimetal NiTe$_2$ leading to topologically protected surface states give rise to fascinating phenomena holding great promise for next-generation electronic and spintronic devices. Key parameters $-$ such as lattice parameter, disorder, vacancies, and electron correlation $-$ significantly influence the electronic structure and, subsequently, the physical properties. To resolve the discrepancy between the theoretical description and experimentally observed topological surface states, we comprehensively investigate the electronic structure of NiTe$_2$ using angle-resolved photoemission spectroscopy and density functional theory. Although the bulk electronic structure is found to be well-described within mean field approaches, an accurate description of topological surface states is obtained only by incorporating surface electronic correlation. We reveal that the strongly correlated surface states forming Dirac-like conical crossing much below Fermi level have hybridized Ni 3$d$ and Te 5$p$ character. These findings underscore the intricate interplay between electron correlation and band topology, broadening our understanding of many-body correlation effects on the topological surface states in quantum materials.