Two-dimensional metal oxides: a first-principles study

Abstract

Since the discovery of graphene[1], two-dimensional (2D) materials have been under intensive study for their unique physical and chemical properties. Although a lot of 2D materials have been reported, more unique materials are still necessary to realize different functions in electronic devices and spintronics. In this work, a family of 2D metal dioxides (MO2, M = Ti, Zr, Hf) is designed for the possible application in electronics and spintronics by first-principles calculations. Different phases of MO2 are considered, and the stable phases are picked out after investigating their stability systematically. The negative formation energies imply that they are possible to be synthesized. The calculated electronic properties show that they are indirect bandgap semiconductors with a wide bandgap of over 3 eV. We further found that nitrogen doping can introduce magnetic properties to MO2, and different magnetic arrangements can be achieved by adjusting the concentration of dopants. Our findings provide a novel 2D material family for nanodevices and guide the design of new 2D materials as well.