Modulation of spin and charge currents through functionalized 2D diamond devices

Abstract

In this study, we explore the potential of functionalized two-dimensional (2D) diamond for spin-dependent electronic devices using first-principles calculations. Specifically, we investigate functionalizations with either hydroxyl (−OH) or fluorine (−F) groups. In the case of an isolated layer, we observe that the quantity and distribution of (−OH) or (−F) on the 2D diamond surface significantly influence the sp 2/sp 3 ratio of the carbon atoms in the layer. As the coverage is reduced, both the band gap and magnetic moment decrease. When the 2D diamond is placed between gold contacts and functionalized with (−OH), it results in a device with lower resistance compared to the (−F) functionalization. We predict that the maximum current achieved in the device increases with decreasing (−OH) surface coverage, while the opposite behavior occurs for (−F). Additionally, the surface coverage alone can alter the direction of current rectification in (−F) functionalized 2D diamonds. For all studied systems, a single spin component contributes to the total current for certain values of applied bias, indicating a spin filter behavior.