Structural dynamics of LaVO3 on the nanosecond time scale

Matthew Brahlek, Vladimir A. Stoica, Jason Lapano, Lei Zhang, Hirofumi Akamatsu, I. Cheng Tung, Venkatraman Gopalan, Donald A. Walko, Haidan Wen, John W. Freeland, Roman Engel-Herbert

Research output: Contribution to journalArticle

Abstract

Due to the strong dependence of electronic properties on the local bonding environment, a full characterization of the structural dynamics in ultrafast experiments is critical. Here, we report the dynamics and structural refinement at nanosecond time scales of a perovskite thin film by combining optical excitation with time-resolved X-ray diffraction. This is achieved by monitoring the temporal response of both integer and half-integer diffraction peaks of LaVO3 in response to an above-band-gap 800 nm pump pulse. We find that the lattice expands by 0.1% out of plane, and the relaxation is characterized by a biexponential decay with 2 and 12 ns time scales. We analyze the relative intensity change in half-integer peaks and show that the distortions to the substructure are small: the oxygen octahedral rotation angles decrease by ∼0.3° and La displacements decrease by ∼0.2 pm, which directly corresponds to an ∼0.8° increase in the V-O-V bond-angles, an in-plane V-O bond length reduction of ∼0.3 pm, and an unchanged out-of-plane bond length. This demonstration of tracking the atomic positions in a pump-probe experiment provides experimentally accessible values for structural and electronic tunability in this class of materials and will stimulate future experiments.

Original languageEnglish (US)
Article number014502
JournalStructural Dynamics
Volume6
Issue number1
DOIs
StatePublished - Jan 1 2019

All Science Journal Classification (ASJC) codes

  • Radiation
  • Instrumentation
  • Condensed Matter Physics
  • Spectroscopy

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    Brahlek, M., Stoica, V. A., Lapano, J., Zhang, L., Akamatsu, H., Tung, I. C., Gopalan, V., Walko, D. A., Wen, H., Freeland, J. W., & Engel-Herbert, R. (2019). Structural dynamics of LaVO3 on the nanosecond time scale. Structural Dynamics, 6(1), [014502]. https://doi.org/10.1063/1.5045704