Charge transfer and strain tuned antiferromagnetism in the two-dimensional CrCl3/[Mo2C(–O)]2 heterojunction

Abstract

Magnetic ordering in two-dimensional materials with atomic level thickness has been one of the most important issues in condensed matter physics and material science. Most previous studies have focused on the two-dimensional ferromagnetic systems, while the antiferromagnetic systems have been much less touched. Here, by using first-principles calculations and Monte Carlo simulation, a two-dimensional antiferromagnetic heterojunction: CrCl₃/[Mo₂C(–O)]₂, is predicted, by tuning the electronic distribution. The ferromagnetic coupling between the Cr–Cr atoms in the CrCl₃/(Mo₂C)₂ heterostructure is enhanced by the transferred electrons from Mo₂C, which will occupy the t_2g orbits of Cr. With the O adsorbed on the Mo₂C, the Cr–Cl bond length increases and the superexchange interaction is decreased. The magnetic ground state changes to antiferromagnetism. More interestingly, under a moderate compressive biaxial strain, its Néel temperature of CrCl₃/(Mo₂C–O)₂ can be significantly increased for the enhanced direct exchange of Cr–Cr atom with a value of 146 K. The heterojunction is useful for two-dimensional spintronic logic, ultrafast magnetodynamic devices and information storage for new generation computer devices.