title: Real-time visualization of nanocrystal solid-solid transformation pathways.
abstract: Measurement and understanding of the microscopic pathways materials follow as they transform is crucial for the design and synthesis of new metastable phases of matter. Here we employ femtosecond single-shot X-ray diffraction techniques to measure the pathways underlying solid-solid phase transitions in cadmium sulfide nanorods, a model system for a general class of martensitic transformations. Using picosecond rise-time laser-generated shocks to trigger the transformation, we directly observe the transition state dynamics associated with the wurtzite-to-rocksalt structural phase transformation in cadmium sulfide with atomic-scale resolution. A stress-dependent transition path is observed. At high peak stresses, the majority of the sample is converted directly into the rocksalt phase with no evidence of an intermediate prior to rocksalt formation. At lower peak stresses, a transient five-coordinated intermediate structure is observed consistent with previous first principles modeling.
authors.affiliation: Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Wittenberg
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Miller
authors.forename: Erzsi
authors.initials: E
authors.lastname: Szilagyi
authors.forename: Katie
authors.initials: K
authors.lastname: Lutker
authors.forename: Florian
authors.initials: F
authors.lastname: Quirin
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Henrik
authors.initials: H
authors.lastname: Lemke
authors.forename: Diling
authors.initials: D
authors.lastname: Zhu
authors.forename: Matthieu
authors.initials: M
authors.lastname: Chollet
authors.forename: Joseph
authors.initials: J
authors.lastname: Robinson
authors.forename: Haidan
authors.initials: H
authors.lastname: Wen
authors.forename: Klaus
authors.initials: K
authors.lastname: Sokolowski-Tinten
authors.forename: A Paul
authors.initials: AP
authors.lastname: Alivisatos
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Lindenberg