Low dimensional magnetism has been powerfully boosted as a promising candidate for numerous applications. The stability of the long-range magnetic order is directly dependent on the electronic structure and the relative strength of the competing magnetic exchange constants. Here, we report a comparative pressure-dependent theoretical and experimental study of the electronic structure and exchange interactions of two-dimensional ferromagnets CrBr3 and Cr2Ge2Te6 . While CrBr3 is found to be a Mott-Hubbard-like insulator, Cr2Ge2Te6 shows a charge-transfer character due to the broader character of the Te 5p bands at the Fermi level. This different electronic behaviour is responsible of the robust insulating state of CrBr3 , in which the magnetic exchange constants evolve monotonically with pressure, and the proximity to a metal-insulator transition predicted for Cr2Ge2Te6 , which causes a non-monotonic evolution of its magnetic ordering temperature. We provide a microscopic understanding for the pressure evolution of the magnetic properties of the two systems.
@article{arxiv.2004.11789,
title = {Electronic structure and magnetic exchange interactions of Cr-based van der Waals ferromagnets. A comparative study between CrBr3 and Cr2Ge2Te6},
author = {Adolfo O. Fumega and S. Blanco-Canosa and H. Babu-Vasili and Jian-Shi Zhou and F. Rivadulla and Victor Pardo},
journal= {arXiv preprint arXiv:2004.11789},
year = {2020}
}