Study of Electron and Hole Qubits in Siligene Monolayer: Ab Initio Calculations

We present a comprehensive first-principles investigation of a two-dimensional siligene monolayer composed of an equal ratio of silicon and germanium atoms. The structural, electronic, and magnetic properties were explored through noncollinear density functional theory simulations. The optimized hexagonal lattice was employed to evaluate the influence of excess charge and spin polarization on system stability and electronic structure. Our results show that the most energetically favorable configuration occurs when a hole is introduced and a spin-down magnetic moment is applied, with this state being preferred by 0.76 meV. Analysis of the magnetization reveals paramagnetic behavior in the neutral system and significant variations in total magnetization between electron- and holedoped configurations. Additionally, hole states were found to localize asymmetrically on opposite sides of the siligene sheet, on Ge and Si atoms, respectively. We also examined the work function of the system and observed that it is sensitive to magnetic orientation only in the neutral configuration, remaining constant in charged states. The highest work function value corresponds to the hole-doped system. Finally, the band structure of the neutral system was calculated, revealing a band gap value within the range of pure silicon and germanium. These findings offer valuable insight into the electronic and spintronic potential of 2D SiGe-based materials.