The first-principles study on the magnetic and electronic properties of Janus Cr-based MXene

Abstract Using the first-principles calculations, the geometric, magnetic and electronic properties of two-dimensional Janus MXenes Cr 2 CAB (A/B = F, O, OH) were investigated. The results show that Cr 2 COF, Cr 2 CO(OH) and Cr 2 CF(OH) all exhibit A-type antiferromagnetic. The Janus MXene Cr 2 CO(OH) and Cr 2 COF are half metals with the atomic orbital of Cr- d and O- p states contributing to the metal states at the Fermi level in spin up channel. However, Cr 2 CF(OH) is a semiconductor. Bader charge and geometric structure analyses show that the electron transfer number difference between the O 2- and F - /OH - groups and the bond length difference between Cr-O and Cr-OH/F lead to an unequal interaction at the two ends, resulting in a transition from semiconductor properties of Cr 2 CT 2 (T = F, OH) to half metal of Cr 2 CAB (A = O; B = F, OH). These findings highlight the importance of surface groups on tuning the magnetic and electronic properties of MXene, which benefits to the applications of two-dimensional Janus MXenes in spintronics.