Multicomponent magneto-orbital order and magneto-orbitons in monolayer VCl3

TL;DR

This paper predicts that monolayer VCl3 exhibits a complex multicomponent ground state with coupled magnetic and orbital orderings, leading to novel collective excitations called magneto-orbitons, tunable by strain.

Contribution

It demonstrates, through first-principles calculations, the emergence of intertwined spin and orbital order in VCl3 monolayer and introduces magneto-orbitons as collective excitations.

Findings

VCl3 monolayer has simultaneous magnetic and orbital order.

Magneto-orbitons are predicted as collective modes of the coupled order.

Strain can tune the spin-orbital interactions in VCl3.

Abstract

Van der Waals monolayers featuring magnetic states provide a fundamental building block for artificial quantum matter. Here, we establish the emergence of a multicomponent ground state featuring magneto-orbital excitations of the 3d2-transition metal trihalide VCl3 monolayer. We show that monolayer VCl3 realizes a ground state with simultaneous magnetic and orbital ordering using density functional theory. Using first-principles methods we derive an effective Hamiltonian with intertwined spin and orbital degree of freedom, which we demonstrate can be tuned by strain. We show that magneto-orbitons appear as the collective modes of this complex order, and arise from coupled orbiton magnon excitations due to the magneto-orbital coupling in the system. Our results establish VCl3 as a promising 2D material to observe emergent magneto-orbital excitations and provide a platform for multicomponent symmetry breaking.