Structural dynamics of LaVO₃ on the nanosecond time scale

Journal Article · 18 January 2019 · Structural Dynamics

DOI: https://doi.org/10.1063/1.5045704 · OSTI ID:1545767

Brahlek, Matthew ^[1]; Stoica, Vladimir A. ^[2]; Lapano, Jason ^[3]; Zhang, Lei ^[4]; Akamatsu, Hirofumi ^[5]; Tung, I-Cheng ^[6]; Gopalan, Venkatraman ^[3]; Walko, Donald A. ^[6]; Wen, Haidan ^[6]; Freeland, John W. ^[6]; Engel-Herbert, Roman ^[3]

---

1. Pennsylvania State Univ., University Park, PA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2. Pennsylvania State Univ., University Park, PA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
3. Pennsylvania State Univ., University Park, PA (United States)
4. Pennsylvania State Univ., University Park, PA (United States); Univ. of California, Berkeley, CA (United States)
5. Pennsylvania State Univ., University Park, PA (United States); Tokyo Inst. of Technology, Yokohama (Japan)
6. Argonne National Lab. (ANL), Argonne, IL (United States)

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 similar to 0.3 degrees and La displacements decrease by similar to 0.2 pm, which directly corresponds to an similar to 0.8 degrees increase in the V-O-V bond-angles, an in-plane V-O bond length reduction of similar to 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.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1545767
• Journal Information: Structural Dynamics, Vol. 6, Issue 1; ISSN 2329-7778
• Publisher: American Crystallographic Association/AIPCopyright Statement
• Country of Publication: United States
• Language: English