Innovative & Complex Metal-Rich Materials
Shalabh Gupta, Sarojalochan Samal, Volodymyr Smetana, Hui Wang
The goal of this project is the discovery and understanding of new, complex metal-rich solids. The effort brings together two solid-state chemists (Corbett, Miller) and a surface chemist (Thiel) to address fundamentals of designing and perfecting atom- and energy-efficient synthetic methods for new, complex metal-rich materials. These materials provide rich potential for new thermoelectrics, magneto-responsive processes, molecular storage, and coatings. This research team combines expertise in high-temperature synthesis, diffraction and structural analysis, ultra-high vacuum science, electronic structure theory, and surface characterization to study complex bulk and surface structures. The strength of the scientific components is demonstrated by past work on bulk structure and surfaces of quasicrystals, and on bulk Zintl phases. If successful, this project will uncover a wealth of new solid-state phases, and develop general principles for understanding their stability and properties, both bulk and surface.
The highly-interwoven topics in this project are:
- To discover and design new materials. Our strategy is to combine experiment, viz. exploratory synthesis and temperature-dependent structure determinations, with electronic structure theory to uncover and ultimately design new families of intermetallic phases and to understand the factors that stabilize both new and known phases. In the next three years, for example, we will elucidate precise atomic distributions in complex intermetallic phases, e.g., gamma-brass structures incorporating 3d elements, e.g., Pd-Zn-Al and Mn-Ga-Sn, and quasicrystal approximants, that will establish chemical guidelines for designing new ternary systems, especially those showing quasiperiodicity and potentially interesting itinerant magnetism. We will also investigate how relativistic effects influence and control structure, bonding, and stabilities of intermetallic phases that incorporate 6th period elements, e.g., distinguishing Hg from Tl in BaHg2Tl2 and the new families of gold cluster networks (J. Corbett, G. Miller).
- To understand surface stability and surface properties of complex metal-rich solids. We will experimentally investigate microscopic and mesoscopic morphology, atomic locations, interfacial growth, friction, and chemical reactivity of Pd-Zn-Al quasicrystals. We will apply the tools developed for the bulk phases, to obtain and understand the surfaces. As an example, theoretical aids for understanding stability, structural features and chemical bonding of complex intermetallic systems will be developed. (P. Thiel, J. Corbett, G. Miller).
- To establish structure-property relationships. We will establish these for complex metal-rich materials in the bulk and at their surfaces as related to both fundamental as well as practical issues, e.g., thermoelectrics, magnetocalorics, hydrogen storage, tribology, and structural behavior. In the next three years, we will study insertion of interstitial atoms, e.g., hydrogen in La-Al phases, or lattice substitution of selected heteroatoms. (J. Corbett, P. Thiel).
Smetana V; Corbett J D; Miller G J . 2013. Na8Au9.8(4)Ga7.2 and Na17Au15.87(2)Ga46.63: The diversity of pseudo 5-fold 0 Cross Mark symmetries in the Na-Au-Ga system. Journal of Solid State Chemistry. 207:21-28.
Smetana V; Miller G J; Corbett J D . 2013. Polyclusters and Substitution Effects in the Na-Au-Ga System: Remarkable Sodium Bonding Characteristics in Polar Intermetallics. Inorganic Chemistry. 52:12502-12510.
Gulo F; Samal S L; Corbett J D . 2013. Substantial Cd-Cd Bonding in Ca6PtCd11: A Condensed Intermetallic Phase Built of Pentagonal Cd, and Rectangular Cd4/2Pt Pyramids. Inorganic Chemistry. 52:10112-10118.
Xie W W; Thimmaiah S; Lamsal J; Liu J; Heitmann T W; Quirinale D; Goldman A I; Pecharsky V; Miller G J . 2013. beta-Mn-Type Co8+xZn12-x as a Defect Cubic Laves Phase: Site Preferences, Magnetism, and Electronic Structure. Inorganic Chemistry. 52:9399-9408.
Xiao C X; Wang L L; Maligal-Ganesh R V; Smetana V; Walen H; Thiel P A; Miller G J; Johnson D D; Huang W Y . 2013. Intermetallic NaAu2 as a Heterogeneous Catalyst for Low-Temperature CO Oxidation. Journal of the American Chemical Society. 135:9592-9595.
Wang C L; Zou J D; Liu J; Mudryk Y; Gschneidner K A; Long Y; Smetana V; Miller G J; Pecharsky V K . 2013. Crystal structure, magnetic properties, and the magnetocaloric effect of Gd5Rh4 and GdRh. Journal of Applied Physics. 113:17a904.
Liu J; Smetana V; Gschneidner K A; Miller G J; Pecharsky V K . 2013. The crystal structure and magnetic properties of Pr117Co56.7Ge112. Journal of Applied Physics. 113:17e120.
Lin X; Bud'ko S L; Thimmaiah S; Canfield P C . 2013. Anisotropic magnetization, resistivity and heat capacity of single crystalline R3Ni2-xSn7 (R=La, Ce, Pr and Nd). Journal of Magnetism and Magnetic Materials. 331:53-61.
Mudryk Y; Manfrinetti P; Smetana V; Liu J; Fornasini M L; Provino A; Pecharsky V K; Miller G J; Gschneidner K A . 2013. Structural disorder and magnetism in rare-earth (R) R117Co54+xSn112 +/- y. Journal of Alloys and Compounds. 557:252-260.