Multicomponent Magneto-Orbital Order and Magneto-Orbitons in Monolayer VCl3

Van der Waals monolayers featuring magnetic states provide fundamental building blocks 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 by using density functional theory. Using first-principles methods we derive an effective Hamiltonian with intertwined spin and orbital degrees 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 is a promising 2D material to observe emergent magneto-orbital excitations and provides a platform for multicomponent symmetry breaking.