Structural stability and electronic properties of multi-functionalized two-dimensional chromium carbides

The feasibility of designing two-dimensional (2D) materials was investigated using monolayer Cr2C, a member of the MXene family, with F and OH functional groups on each side of the surface. Interestingly, this study shows that the magnetic and electronic properties of Cr2C with F and OH functional groups (i.e., Cr2CF(OH), with one functional group on each side) can be predicted using previously known properties of Cr2C with only one kind of functional group (i.e., either F or OH on both sides). Unlike typical functionalized 2D materials with different functional groups, each functional group of Cr2CF(OH) has a negligible effect on the magnetic and electronic properties of the other side. This unique phenomenon results from the small differences in geometry between the functional groups, such as the coordination number, bond length, and thickness; the properties themselves come from those of Cr2CF2 and Cr2C(OH)2, despite having different functional groups. Due to the preserved magnetic moments of the Cr atoms bound with each functional group, Cr2CF(OH) exhibits ferrimagnetism. Likewise, semiconducting characters are present because the atomic contributions of each energy level from Cr2CF2 and Cr2C(OH)2 are maintained. Thus, the present work demonstrates that a combination of functional groups that shows certain desired properties can be selected when designing Cr2C-based spintronic and electronic devices.