skip to main content
Idioma:

Imaging transient melting of a nanocrystal using an X-ray laser

Clark, Jesse N ; Loren Beitra ; Gang Xiong ; David M. Fritz ; Henrik T. Lemke ; Diling Zhu ; Matthieu Chollet ; Garth J. Williams ; Marc M. Messerschmidt ; Brian Abbey ; Ross J. Harder ; Alexander M. Korsunsky ; Justin S. Wark ; David A. Reis ; Ian K. Robinson

Proceedings of the National Academy of Sciences - PNAS, 2015-06, Vol.112 (24), p.7444-7448 [Periódico revisado por pares]

United States: National Academy of Sciences

Texto completo disponível

Citações Citado por
  • Título:
    Imaging transient melting of a nanocrystal using an X-ray laser
  • Autor: Clark, Jesse N ; Loren Beitra ; Gang Xiong ; David M. Fritz ; Henrik T. Lemke ; Diling Zhu ; Matthieu Chollet ; Garth J. Williams ; Marc M. Messerschmidt ; Brian Abbey ; Ross J. Harder ; Alexander M. Korsunsky ; Justin S. Wark ; David A. Reis ; Ian K. Robinson
  • Assuntos: coherent diffraction ; image analysis ; Lasers ; Melting ; Nanocrystals ; Nanoparticles ; phase transition ; Phase transitions ; Physical Sciences ; pump-probe ; ultrafast imaging ; X-radiation ; X-ray laser
  • É parte de: Proceedings of the National Academy of Sciences - PNAS, 2015-06, Vol.112 (24), p.7444-7448
  • Notas: http://dx.doi.org/10.1073/pnas.1417678112
    ObjectType-Article-1
    SourceType-Scholarly Journals-1
    ObjectType-Feature-2
    content type line 23
    USDOE
    AC02-76SF00515
    Edited by Henry C. Kapteyn, University of Colorado Boulder, Boulder, CO, and approved May 5, 2015 (received for review September 12, 2014)
    Author contributions: J.N.C., L.B., G.J.W., R.J.H., and I.K.R. designed research; J.N.C., L.B., G.X., D.M.F., H.T.L., D.Z., M.C., G.J.W., M.M.M., B.A., R.J.H., A.M.K., J.S.W., D.A.R., and I.K.R. performed research; J.N.C. and I.K.R. analyzed data; and J.N.C., D.A.R., and I.K.R. wrote the paper.
  • Descrição: There is a fundamental interest in studying photoinduced dynamics in nanoparticles and nanostructures as it provides insight into their mechanical and thermal properties out of equilibrium and during phase transitions. Nanoparticles can display significantly different properties from the bulk, which is due to the interplay between their size, morphology, crystallinity, defect concentration, and surface properties. Particularly interesting scenarios arise when nanoparticles undergo phase transitions, such as melting induced by an optical laser. Current theoretical evidence suggests that nanoparticles can undergo reversible nonhomogenous melting with the formation of a core-shell structure consisting of a liquid outer layer. To date, studies from ensembles of nanoparticles have tentatively suggested that such mechanisms are present. Here we demonstrate imaging transient melting and softening of the acoustic phonon modes of an individual gold nanocrystal, using an X-ray free electron laser. The results demonstrate that the transient melting is reversible and nonhomogenous, consistent with a core-shell model of melting. The results have implications for understanding transient processes in nanoparticles and determining their elastic properties as they undergo phase transitions. Significance Despite phase transitions, such as melting, being ubiquitous in nature, understanding what occurs at the nanoscale (such as in nanocrystals) has so far remained challenging. With ensemble studies of nanocrystals it is often difficult to discriminate between intrinsic size-dependent properties and effects due to sample size and shape dispersity. Here, using an X-ray free electron laser we image the reversible melting of an individual nanocrystal induced by an ultrashort laser. It is revealed that the melting occurs transiently, repeatably, and inhomogeneously. This is consistent with a core-shell model where the exterior is melted and a solid core remains. These findings reveal, unambiguously, that core-shell melting occurs, which has important implications for understanding nanoscale phenomena.
  • Editor: United States: National Academy of Sciences
  • Idioma: Inglês
Links
Voltar para lista de resultados
Ir para página anteriorAnterior Resultado  9 AvançarIr para próxima página

  • Realização: ABCD-USP USP   Logos de Redes Sociais: Freepik

Buscando em bases de dados remotas. Favor aguardar.