Local distortions and long range magnetic order in VI3 and CrI3

In 2D van der Waals trihalides ferromagnets MX3 - where M is a transition metal and X a halogen - the local electronic configuration around the metal centers determines both the long range magnetic order and the electronic properties. In CrI3, the typical coordination of Cr atoms is octahedral and most of its known magnetic and electronic properties arise from it. For VI3 instead, it was recently suggested in theoretical papers that the electronic character of V d-states stabilizes a trigonal distorted configuration via a Jahn-Teller (JT) mechanism. With this experiment, we want to perform X-ray Natural Linear Dichroism (XNLD) measurements to check the orbital order in bulk VI3 and compare it with the predictions.