School Colloquia Series - Electronic shell structure and the thermodynamic stability of clusters
Speaker: Associate Professor Nicola Gaston, University of Auckland
Abstract: Atomic clusters have long been studied as the natural building blocks of materials, from which we can obtain insight into the packing arrangements and electronic structures that arise as the size of the cluster grows, atom by atom, to determine functional properties of the solid state. However, the often non-monotonic size-variation in properties has also presented us with a range of fascinating phenomena that enable us to think differently about the reasons behind the thermodynamic stability of particular phases, and perhaps, about how to design new ones.
In this talk, I’ll discuss our work exploring and explaining the greater-than-bulk melting temperatures of small gallium clusters: how can a change of phase from solid to liquid change the preference for a specific dimensionality, of a sufficiently small object?1 How does this relate to the electronic interactions within the cluster, and its electronic phase, i.e. metallicity?2 What are the prospects for using the highly variable properties of small clusters to design materials with desired, and tunable, electronic properties?3,4
1) K. G. Steenbergen & N. Gaston. A Two-Dimensional Liquid Structure Explains the Elevated Melting Temperatures of Gallium Nanoclusters. Nano Lett., 16, 21 (2016).
2) K. G. Steenbergen, and N. Gaston. Quantum Size Effects in the Size-temperature Phase Diagram of Gallium: Structural Characterization of Shapeshifting Clusters. Chem – A Eur. J. 21, 2862–2869, (2015).
3) L. Hammerschmidt, J. Schacht, & N. Gaston. First-principles calculations of the electronic structure & bonding in metal cluster–fullerene materials considered within the superatomic framework. Phys. Chem. Chem. Phys. 18, 32541 (2016).
4) J. T. A Gilmour, L. Hammerschmidt, J. Schacht, N. Gaston. Superatomic states in nickel clusters: Revising the prospects for transition metal based superatoms. J. Chem. Phys. 147, 154307 (2017).