In this work, a first-principles study of Na 2O and K 2O monolayers, and their Janus structure has been carried out using density functional theory (DFT) calculations based on the...

In this work, the structural, electronic, and magnetic properties of arsenene monolayer doped with germanium (Ge) and nitrogen (N) atoms are investigated using density functional theory (DFT) calculations. Pristine monolayer is dynamically stable and it possesses a wide indirect band gap. Ge doping induces magnetic semiconductor (MS) nature generated by the semiconductor behavior in both spin channels with significant spin asymmetry around the Fermi level. The dopant produces mainly magnetic properties. Upon increasing the doping concentration, different doping configurations along armchair, zigzag edges, and hexagonal ring have been proposed. The MS nature is retained with an odd number of Ge atoms, meanwhile an even number leads to the disappearance of magnetism. In contrast, N doping induces a gap reduction of 11.80%, preserving the non-magnetic nature. At higher doping level, different electronic features including semiconductor, nearly semimetallic, and metallic natures are obtained depending on the doping concentration and configurations. In addition, the formation energy and cohesive energy are calculated to analyze the systems’ stability. Our results show that different doping arrangements induce novel features in arsenene monolayer for applications in spintronic and optoelectronic devices.

Doping has been widely employed as an efficient method to diversify the materials properties. In this work, the structural, magnetic, and electronic properties of pristine, aluminum(Al)-, and silicon(Si)-doped blue phosphorene monolayer are investigated using first-principles calculations. Pristine monolayer is a non-magnetic wide gap semiconductor with a band gap of 1.81 eV. The 1Si-doped system is a ferromagnetic semiconductor. However, the magnetism is turned off when increasing the dopant composition with small Si-Si distance. Further separating the dopants recovers step by step the magnetic properties, and an antiferromagnetic(AFM)-ferromagnetic(FM) state transition will take place at large dopants separation. In contrast, Al doping retains the non-magnetic semiconductor behavior of blue phosphorene. However, significant energy gap reduction is achieved, where this parameter exhibits a strong dependence on the dopant concentration and doping configuration. Such control may also induce the indirect-direct gap transition. Our results introduce prospective two-dimensional (2D) materials for applications in spintronic and optoelectronic nano devices, which can be realized and stabilized in experiments as suggested by the calculated formation and cohesive energies.