Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster Session I
HL 13.10: Poster
Montag, 12. März 2018, 17:30–19:30, Poster B
Optical properties the Ferromagnetic CrI3 monolayer — •Claudia Cardoso1, David Soriano1, and Joaquín Fernández-Rossier1,2 — 1International Iberian Nanotechnology Laboratory (INL), Braga, Portugal — 2Departamento de Física Aplicada, Universidad de Alicant, Spain
The recent reports of ferromagnetic order in two dimensional crystals sign the beginning of a new chapter in the field of 2D materials. Bulk CrI3 is a layered van der Waals ferromagnet and, in its monolayer form, a 2D ferromagnet. Distinct from the Wannier-Mott excitons which dominate the optical response in 2D van der Waals semiconductors, the recently reported absorption photoluminescence measurements on CrI3 were explained in terms of ligand-field, charge-transfer and parity-forbidden d−d transition characteristic of Cr3+ complexes.
The aim of the present work is to go beyond phenomenological models, and study the ferromagnetic CrI3 monolayer optical properties from first principles. On the one hand, it is possible to describe the properties of a magnetic system in terms of effective single spin Hamiltonians, yet the determination of the different parameters requires experimental input. On the other hand, Density Functional Theory (DFT) provides an accurate description of the ground state electronic properties, however it does not describe low energy spin excitations. By combining these two approaches we derive the effective spin Hamiltonian starting from an atomistic DFT description. This method allows us to interpret the experimental findings and identify the origin of the transitions in the recently reported photoluminescence measurements.