title: Thermally stable coexistence of liquid and solid phases in gallium nanoparticles.
abstract: Gallium (Ga), a group III metal, is of fundamental interest due to its polymorphism and unusual phase transition behaviours. New solid phases have been observed when Ga is confined at the nanoscale. Herein, we demonstrate the stable coexistence, from 180 K to 800 K, of the unexpected solid γ-phase core and a liquid shell in substrate-supported Ga nanoparticles. We show that the support plays a fundamental role in determining Ga nanoparticle phases, with the driving forces for the nucleation of the γ-phase being the Laplace pressure in the nanoparticles and the epitaxial relationship of this phase to the substrate. We exploit the change in the amplitude of the evolving surface plasmon resonance of Ga nanoparticle ensembles during synthesis to reveal in real time the solid core formation in the liquid Ga nanoparticle. Finally, we provide a general framework for understanding how nanoscale confinement, interfacial and surface energies, and crystalline relationships to the substrate enable and stabilize the coexistence of unexpected phases.
authors.affiliation: Institute of Nanotechnology, CNR-NANOTEC, via Orabona 4, 70126 Bari, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Losurdo
authors.affiliation: Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, Crawley, Western Australia 6009, Australia.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Suvorova
authors.affiliation: Bio21 Institute, University of Melbourne, 161 Barry Street, Parkville 3010, Victoria, Australia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Rubanov
authors.affiliation: Center for Surface- and Nanoanalytics, Johannes Kepler University Linz, Altenbergerstr. 69, 4040 Linz, Austria.
authors.forename: Kurt
authors.initials: K
authors.lastname: Hingerl
authors.affiliation: Army Research Office, Engineering Sciences Directorate, Durham, North Carolina 27708, USA.|Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708, USA.
authors.forename: April S
authors.initials: AS
authors.lastname: Brown