Research Projects

Oxide quasicrystal (OQC) is a new topic of interest in intermetallic quasicrystals (QC). It is identified as BaTiO3-based one-atom thick overlayer on Pt(111) that forms QC structure. However, the complete structure details, such as the elemental/chemical identity of the bright protrusion observed in scanning tunneling microscopy (STM), and other atomic sites of the constituent elements (Ba, Ti, and O) and their contribution to the observed structure, are not known to date. The current understanding is that the identical feature in STM data originates from possibly higher density of states (DOS) of Ti compared to weaker DOS of Ba/O. To study OQC, researchers prefer to grow Bi2O3, Fe2O3, and then BiFeO3 as starting choices on Pt(111). Sr-Ti-O and Ba-Ti-O on various substrates form OQC, and some approximants are formed. Bi/Fe might give rise to spin texture due to the aperiodic nature of the surface, heavy atomic number, and breaking of inversion symmetry at the surface. To perform growth and structural determination studies, researchers aim to establish state-of-the-art ultrahigh vacuum based STM/STS investigation tools, using a homemade version. This will allow for tailoring OQC suitable for technological applications, such as as a buffer layer for electron confinement due to wavefunction mismatch. The unique surface structure with characteristic adsorption sites and chemical reactivities of QC will be used to understand the interplay between inter-molecule and molecule-substrate interactions of adsorbed organic molecules.