Defect induced ferromagnetism in a two-dimensional metal-organic framework

Two-dimensional ferromagnetic materials are potential candidates that can be integrated with the current nanoelectronic and spintronic device architecture. The latest trends in designing spintronic devices are mainly based on two-dimensional (2D) inorganic compounds. Here, we present a study based on first-principles density functional calculations where we design a 2D ferromagnetic material within the family of metal-organic frameworks. Starting from the inorganic CrI3 compound, we demonstrate that a chromium-based metal-organic compound i.e. Cr(COOH)(3) can be stabilized in a ferromagnetic state compared to the other possible antiferromagnetic states. The proposed structure of Cr(COOH)(3) is found to be thermodynamically stable, but its dynamic stability could not be verified because of complexity into the structure. The lowest energy magnetic configuration of pure Cr(COOH)(3) turns out to be antiferromagnetic. However, our calculations suggest that the presence of positively charged Cr-vacancy defects can stabilize the ferromagnetic state over antiferromagnetic orderings. The presence of delocalized holes is found to be responsible for favoring the ferromagnetic ordering.