1. When and why are ultrathin films of metallic oxides not metallic? Jiandi Zhang, Louisiana State University & Agricultural and Mechanical College, DMR 1005562 In contrast with the metallic or even superconducting phenomenon emerging at the interface of two insulating oxides (i.g., LaAlO3/SrTiO3), several ultra thin films of metallic oxides exhibit non metallic behavior, challenging our understanding of these materials at interface. The main issue is to understand when and why are ultrathin films of metallic oxides not metallic. We have been working on both SrVO3and La1-xSrxMnO3 (x=0.3) (LSMO) films on SrTiO3 (STO) (001) substrate with our laser-MBE growth and in-situ characterization for structure, chemical composition, and electronic properties, as well as ex-situ transport measurements. For LSMO films, we have found a minimum critical thickness for metallicity as well as a giant response in film transport to the substrate structural phase transition at T = 106 K. These results clearly indicate many new and exciting phenomena can emerge in CMEs through broken symmetry as well as spatial confinement. STM images on the unreconstructed surface of (a) STO (with electron diffraction image as the inset) and (c) 10 unit cell (U.C.) LSMO film as well as (b) a ball model of the interface between LSMO/STO; (d) the metal-insulator transition temperature (TC) vs. the thickness of the films grown in different oxygen partial pressure, with the inset for the minimum non-metallic ‘deal-layer’ thickness evolution; and (e) normalized resistivity near the structural transition temperature (~106 K) of the substrate for 5, 6, and 7 U.C. thickness of the stoichiometric films.

2. When and why are ultrathin films of metallic oxides not metallic? Jiandi Zhang, Louisiana State University & Agricultural and Mechanical College, DMR 1005562 The research training mainly focuses on the training of graduate as well as undergraduate students. Andrew Antony is undergraduate student in physics and a member of the LSU “Chancellor’s Future Leaders in Research” program. He is working with our graduate students for the growth of oxide films, participating in some basic materials characterization. His undergraduate research is to study the chemical composition in oxide films by using AR-XPS. He is also involved in some design of experimental setup with our graduate students. Dalgis Mesa is Hispanic graduate student and supported by this grant. Her thesis research focuses on correlation between lattice and spin degrees of freedom in the bulk transition-metal oxides related to the project by using elastic and inelastic neutron scattering, especially the metal-to-insulator transition accompanied with magnetic phase transition in doped manganites and ruthenates. She is using national neutron facilities including these at ORNL and NIST. An international collaboration program on both research and education for exploring emergent phenomena at the surface and interface of correlated electron materials has established between LSU (including Prof. E.W. Plummer and Prof. R. Jin) and the Institute of Physics (IOP), the Chinese Academy of Science. The program focuses on the training of dual-degree Ph. D. students. The picture of the collaborative group was taken at IOP.