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).
Gourdon O; Izaola Z; Elcoro L; Petricek V; Miller G J . 2009. Structure Determination of Two Modulated gamma-Brass Structures in the Zn-Pd System through a (3+1)-Dimensional Space Description. Inorganic Chemistry. 48:9715-9722.
Unal B; Sato Y; McCarty K F; Bartelt N C; Duden T; Jenks C J; Schmid A K; Thiel P A . 2009. Work function of a quasicrystal surface: Icosahedral Al-Pd-Mn. Journal of Vacuum Science & Technology A. 27:1249-1250.
Li B; Kim S J; Miller G J; Corbett J D . 2009. Gold Tetrahedra as Building Blocks in K3Au5Tr (Tr = In, Tl) and Rb2Au3Tl and in Other Compounds: A Broad Group of Electron-Poor Intermetallic Phases. Inorganic Chemistry. 48:6573-6583.
Duguet T; Unal B; de Weerd M C; Ledieu J; Ribeiro R A; Canfield P C; Deloudi S; Steurer W; Jenks C J; Dubois J M; Fournee V; Thiel P A . 2009. Twofold surface of the decagonal Al-Cu-Co quasicrystal. Physical Review B. 80:024201.
Dai J C; Gupta S; Gourdon O; Kim H J; Corbett J D . 2009. BaHg2Tl2. An Unusual Polar Intermetallic Phase with Strong Differentiation between the Neighboring Elements Mercury and Thallium. Journal of the American Chemical Society. 131:8677-8682.
Lin Q S; Corbett J D . 2009. Centric and Non-centric Ca3Au similar to 7.5Ge similar to 3.5: Electron-Poor Derivatives of La3Al11. Syntheses, Structures, and Bonding Analyses. Inorganic Chemistry. 48:5403-5411.
Svitlyk V; Fei F; Kracher A; Mozharivskyj Y . 2009. Quaternary Gd4Ni2Sb1 +/- xSi2 +/- x and Gd4Ni2Bi1 +/- xSi2 +/- x: Crystal structure, homogeneity regions and magnetic behavior. Solid State Sciences. 11:1083-1087.
Gupta S; Leon-Escamilla E A; Wang F; Miller G J; Corbett J D . 2009. R(5)Pn(3)-type Phases of the Heavier Trivalent Rare-Earth-Metal Pnictides (Pn = Sb, Bi): New Phase Transitions for Er5Sb3 and Tm5Sb3. Inorganic Chemistry. 48:4362-4371.
Unal B; Fournee V; Thiel P A; Evans J W . 2009. Structure and Growth of Height-Selected Ag Islands on Fivefold i-AlPdMn Quasicrystalline Surfaces: STM Analysis and Step Dynamics Modeling. Physical Review Letters. 102:196103.