Graphitic silicon nitride: a metal-free ferromagnet with charge and spin current rectification

As a first example, herein we show that g-Si(4)N(3) is expected to act as a metal-free ferromagnet featuring both charge and spin current rectification simultaneously. Such rectification is crucial for envisioning devices that contain both logic and memory functionality on a single chip. The spin coherent quantum-transport calculations on g-Si(4)N(3) reveal that the chosen system is a unique molecular spin filter, the current-voltage characteristics of which is asymmetric in nature, which can create a perfect background for synchronous charge and spin current rectification. To shed light on this highly unusual in-silico observation, we have meticulously inspected the bias-dependent modulation of the spin-polarized eigenstates. The results indicate that, whereas only the localized 2p orbitals of the outer-ring (OR) Si atoms participate in the transmission process in the positive bias, both OR Si and N atoms contribute in the reverse bias. Furthermore, we have evaluated the spin-polarized electron-transfer rate in the tunneling regime, and the results demonstrate that the transfer rates are unequal in the positive and negative bias range, leading to the possible realization of a simultaneous logic-memory device.