Effects of biaxial strain on the electronic structure, vibrational properties and electron-phonon coupling of silicene

We present results of ab-initio calculations for the electronic structure, vibrational properties, electron-phonon coupling, and conventional superconductivity for silicene under biaxial strain for deformations up to 18%. The calculations were performed using the Plane-Waves and Pseudopotential method, with the GGA-PBE exchange-correlation functional. Dynamical matrices and e-ph coupling properties were computed with the linear response theory. The superconducting gap and the critical temperature were calculated employing the multiband Eliashberg formalism. We found that biaxial strain shifts the sigma-band located above the Fermi level at the Gamma point to lower energies and the Dirac point is shifted above the Fermi level, producing an electronic topological transition in the Fermi surface. Thus, silicene under biaxial strain becomes metallic for deformations larger than 8%. Hence, we found that biaxial strain produces strong changes in the electronic structure that enhances the electron-phonon coupling and induce conventional superconductivity in silicene.