First-principles study on the structural and electronic properties of Li4SiO4 and Al-doped Li4SiO4

The structural and electronic properties of Li4SiO4 and Al-doped Li4SiO4 have been investigated using first-principles density functional theory. The crystal structure is fully relaxed. It can be concluded that the crystalline structure has been expanded as Al doped. The calculated total energies indicate that the Al atoms may occupy the Si 1, Si 2, Si 5 and Si 6 in preference to the other Si sits. The direct band gap of Li4SiO4 is 5.07 eV while Al-doped Li4SiO4 has a direct band gap of 4.78 eV. The values of the band gaps indicate that both of them are insulators. The value of the band gap reduces as Al-doped, which means that the conductivity could be improved as Al-doped.