Orbital mixing and strong Hund's coupling stabilize spin order in van der Waals ferromagnet CrI3

Abstract

Recent years have seen a vast increase in research into van der Waals magnetic materials. In many of these systems, magnetism is introduced via light 3d-transition metal elements, combined with chalcogenides or halogens. Despite the high technological promise in the field of spintronics, the connection between the d-orbital configuration and the occurrence of low-dimensional magnetic order is currently unclear. Here we address the prototypical two-dimensional ferromagnet CrI3, via complementary spectroscopies and density functional theory calculations. We reveal the electronic structure and orbital character of bulk CrI3 in the paramagnetic and ferromagnetic phases, describing the couplings underpinning its energy diagram, and providing a robust experimental demonstration that the stabilization of ferromagnetism is attributable to orbital mixing between I p and Cr eg states, and to the presence of strong Hund's coupling. These findings reveal the microscopic connection between orbital and spin degrees of freedom, providing fundamental insights into the behavior of low-dimensional magnetic materials.

References in corpus (15)

• Restoring the density-gradient expansion for exchange in solids and surfaces
• Generalized gradient approximation for solids and their surfaces
• Magnetic 2D materials and heterostructures
• Magnetic Two-Dimensional Chromium Trihalides: A Theoretical Perspective
• Microscopic mechanism for higher-spin Kitaev model
• Magnetic polaron and antiferro-ferromagnetic transition in doped bilayer CrI${}_3$
• Magnetic properties of bilayer VI3: Role of trigonal crystal field and electric-field tuning
• Electronic state unfolding for plane waves: energy bands, Fermi surfaces and spectral functions
• On-site and inter-site Hubbard corrections in magnetic monolayers: The case of FePS${}_3$ and CrI${}_3$
• X-ray magnetic circular dichroism and photoemission study of the diluted ferromagnetic semiconductor Zn${}_{1-x}$Cr${}_x$Te
• Superexchange and spin-orbit coupling in monolayer and bilayer chromium trihalides
• Dispersive dark excitons in van der Waals ferromagnet CrI3
• Anisotropic hybridization probed by polarization dependent x-ray absorption spectroscopy in VI3 van der Waals Mott ferromagnet
• Orbital correlations in ultrathin films of late transition metals
• Evidence of temperature-dependent interplay between spin and orbital moment in van der Waals ferromagnet VI3