The effect of charge carrier doping on electric polarization and mobility in bilayer NiCl2

Based on first-principles calculations, we discuss the effects of charge carrier doping on polarization and electron mobility in the bilayer sliding ferroelectric material NiCl2. The bilayer NiCl2 belongs to a polar point group, which can induce spontaneous out-of-plane polarization. It further reveals that polarization reversal can facilitate interlayer sliding through the low-symmetry paraelectric phase structure connecting the polarized structures. Carrier doping can affect polarization, which can be explained by the number of charge carriers in the conduction and valence bands of the doped/undoped system near the Fermi surface. This charge quantity can be obtained through charge density integration. In addition, we find that electron doping can tune the electron mobility at different temperatures, and as the temperature increases, mobility continuously decreases; this process is influenced by three scattering mechanisms. The above results provide a new perspective for designing novel charge carrier-influenced sliding ferroelectric material devices.