Stability and electronic properties of SiGe-based 2D layered structures

The structural and electronic properties of the in-plane hybrids consisting of siligene (SiGe), and its derivatives in both mono and bilayer forms are investigated within density functional theory. Among several pristine and hydrogenated configurations, the so-called chair conformation is energetically favorable for monolayers. On the other hand, the bilayer siligane (HSiGeH) prefers AB-stacked chair conformation and bilayer siligone (HSiGe) prefers AA-stacked buckled conformation. In SiGe, the Dirac-cone character is predicted to be retained. HSiGe is a magnetic semiconductor with a band gap of similar to 0.6 eV. The electronic properties show tunability under mechanical strain and transverse electric field; (i) the energy gap opens up in the SiGe bilayer, (ii) a direct-to-indirect gap transition is predicted by the applied strain in the HSiGeH bilayer, and (iii) a semiconductor-to-metal transition is predicted for HSiGe and HSiGeH bilayers under the application of strain and electric field, thus suggesting SiGe and its derivatives to be a potential candidate for electronic devices at nanoscale.