Orbital-Ordering Driven Simultaneous Tunability of Magnetism and Electric Polarization in Strained Monolayer VCl 3

• Published in: Chinese physics letters Vol. 41; no. 4; p. 47501
• Main Authors: Guo 郭, Deping 的坪, Wang 王, Cong 聪, Wang 王, Lvjin 侣锦, Lu 陆, Yunhao 赟豪, Wu 吴, Hua 骅, Zhang 张, Yanning 妍宁, Ji 季, Wei 威
• Format: Journal Article
• Language: English
• Published: 01.04.2024
• ISSN: 0256-307X; 1741-3540
• DOI: 10.1088/0256-307X/41/4/047501

Two-dimensional (2D) van der Waals magnetic materials have promising and versatile electronic and magnetic properties in the 2D limit, indicating a considerable potential to advance spintronic applications. Theoretical predictions thus far have not ascertained whether monolayer VCl 3 is a ferromagnetic (FM) or anti-FM monolayer; this also remains to be experimentally verified. We theoretically investigate the influence of potential factors, including C 3 symmetry breaking, orbital ordering, epitaxial strain, and charge doping, on the magnetic ground state. Utilizing first-principles calculations, we predict a collinear type-III FM ground state in monolayer VCl 3 with a broken C 3 symmetry, wherein only the former two of three t 2g orbitals ( a 1g , e g 2 π and e g 1 π ) are occupied. The atomic layer thickness and bond angles of monolayer VCl 3 undergo abrupt changes driven by an orbital ordering switch, resulting in concomitant structural and magnetic phase transitions. Introducing doping to the underlying Cl atoms of monolayer VCl 3 without C 3 symmetry simultaneously induces in- and out-of-plane polarizations. This can achieve a multiferroic phase transition if combined with the discovered adjustments of magnetic ground state and polarization magnitude under strain. The establishment of an orbital-ordering driven regulatory mechanism can facilitate deeper exploration and comprehension of magnetic properties of strongly correlated systems in monolayer VCl 3 .