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 language | English |
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Article number | 014502 |
Journal | Structural Dynamics |
Volume | 6 |
Issue number | 1 |
DOIs | |
State | Published - Jan 1 2019 |
Externally published | Yes |
Funding
We would like to thank R. Averitt, D. Lovinger, M. Gu, and J. M. Rondinelli for discussion. M.B. and R.E.H. acknowledge the Department of Energy (Grant No. DE-SC0012375) for film growth, X-ray measurements, travel support, data analysis, and preparation of this manuscript. V.A.S., H.A., H.W., V.G., and J.W.F. acknowledge the Department of Energy (Grant No. DESC0012375) for assistance in X-ray measurements, data analysis, and preparation of this manuscript. The work at the Advanced Photon Source, Argonne, was supported by the U.S. Department of Energy, Office of Science under Grant No. DEAC02-06CH11357. J.L. and L.Z. acknowledge the support of the National Science Foundation through the Penn State MRSEC Program DMR-1420620 (J.L. and R.E.H.) as well as NSF Career Grant No. DMR-1352502 (L.Z. and R.E.H.) for assistance in film growth and X-ray measurements.