Photoluminescence from Cr3+ excited orbital states in magnetically ordered CrCl3

Abstract Control of magnetic order through optical manipulation of orbital states can be realized in a wide range of materials, including insulators. In the latter case, electrons are excited into different electronic states, whose character may be a complex result of spin-orbit-lattice coupling. Here, we use a combination of polarization-resolved photoluminescence spectroscopy and density functional theory calculations to study excited Cr 3+ ions in bulk, insulating, antiferromagnetic CrCl 3 . Our results demonstrate a temperature-dependent preferential polarization direction below ~17 K, which reorients in the presence of an applied in-plane magnetic field. Density functional theory calculations reveal a local distortion of the ligand field and the generation of out-of-plane spin and orbital moments, following the excitation of Cr 3+ ion. These changes link the photoluminescence polarization to the magnetic state of CrCl 3 . Our findings provide insight into the electronic structure of excited-state Cr 3+ ions and suggest that CrCl 3 is a promising candidate for opto-orbitronic applications.