Tuning orbital-selective Mottness in 2D Hund's metal

Abstract

Two-dimensional materials have great potential for investigating fundamental physics and device applications due to their low-dimensionality.1 In addition, electronic correlation, which provides rich emergent phenomena, can further expand the functionalities of two-dimensional materials.2 To merge their compelling features, realization of the two-dimensional correlated systems and effective control of the electronic structures are important. Here, we observed orbital-selective Mott transition in monolayer correlated systems by epitaxial strain. The monolayer SrRuO3 films, one of strongly correlated oxides, with epitaxial strain were realized. The Jahn-Teller distortion due to the epitaxial strain induced crystal field splitting between Ru t2g orbitals, leading to electronic structure changes. The metal to orbital-selective Mott transition was observed by in-situ angle-resolved photoemission spectroscopy. Such modulation of electronic structures originates from change of electron filling between Ru t2g orbitals. This study paves a way for investigating two-dimensional correlated physics, demonstrating modulation of electronic structures in correlated oxide monolayer systems.

[1]          K. S. Novoselev et al., Nature 438, 197-200 (2005)

[2]          B. Sohn et al., Nature Communicaions 12, 6171 (2021)