Strain Engineered Band Gaps and Electronic Properties in PbPdO₂ and PbPdCoO₂ Slabs.

Electronic structure and corresponding electrical properties of PbPdO₂ and PbPdCoO₂ ultrathin slabs with (002) preferred orientation were systematically investigated using first-principles calculations. The calculated results revealed the strain induced evidently the changes of band structure and carrier concentration in both slabs. It was also found that PbPdO₂ and PbPdCoO₂ ultrathin slabs exhibited evident differences in the external strain dependence of the band gap and charge carrier concentration, which was strongly dependent on bond angle and bond length induced by in-plane anisotropy strain. Interestingly, the carrier concentration of the PbPdCoO₂ slab could increase up to 5⁻6 orders of magnitude with the help of external strain, which could explain the potential mechanism behind the observed colossal strain-induced electrical behaviors. This work demonstrated that the influence of the doping effect in the case of PbPdO₂ could be a potentially fruitful approach for the development of promising piezoresistive materials.