Enhancement of ferromagnetism for VI3 monolayer

Abstract Transition metal trihalides have recently received tremendous attention and the intrinsic ferromagnetism can even survive down to monolayer limit. One of the family numbers, i.e., layered van-der-Waals VI3 crystal, has been widely studied, yet little has been revealed for its monolayer counterpart. Herein, electronic and magnetic behaviour has been studied, based on density functional theory, including both electron correlation (U) and spin–orbit coupling (SOC). In contrast to previous study, the insulating character of VI3 is well rationalized by the extra V atom in the hollow site. Moreover, the ferromagnetic interaction is found to be originated from d x 2 - y 2 - p x , p y - d x 2 - y 2 , a strong pdσ hybridization, based on a model of hole resident on I 5p texture. Strategies have been proposed to improve the critical temperature, in which I deficiency is a powerful tool via triggering additional itinerant ferromagnetic path via d x 2 - y 2 - p x - d x 2 - y 2 .