Insights into the interfaces of VO2(M) and VO2(B) polymorphs with different substrates

Abstract

The phenomena arising at the interface between oxide materials and substrates can fundamentally and practically change the physical and chemical properties of the materials themselves. In this study, we employed density functional theory (DFT) calculations to elucidate the stability and optical properties of VO₂(M) and VO₂(B) interactions with substrates of sapphire(c-cut), sapphire(r-cut), SrTiO₃(001), SrTiO₃(111), SrNbO₃(001), SrNbO₃(111), LaAlO₃(c-cut), and LaAlO₃(r-cut). The surface calculations showed that the fully relaxed SrTiO₃(111) and SrNbO₃(001) possess the highest energies of 31.8 eV nm⁻² and 21.15 eV nm⁻² relative to other slabs, before optimizing with VO₂(M) and VO₂(B) polymorphs, respectively. The calculated adsorption energy indicated that the interface of VO₂(M) and VO₂(B) structures showed more stability on SrTiO₃(001) and SrTiO₃(111), with adsorption energy values of 2.83 eV and 0.91 eV, respectively. Furthermore, the optical absorption properties of the highest and lowest stable interfaces have been evaluated. The outcomes predicted that VO₂(M)@SrTiO₃(001) and VO₂(B)@SrTiO₃(111) have their optical adsorption in the visible light range, while VO₂(M)@sapphire(c-cut) and VO₂(B)@sapphire(c-cut) showed the main adsorption peak in the infrared region.