TY - JOUR A1 - Schick, Daniel A1 - Herzog, Marc A1 - Wen, Haidan A1 - Chen, Pice A1 - Adamo, Carolina A1 - Gaal, Peter A1 - Schlom, Darrell G. A1 - Evans, Paul G. A1 - Li, Yuelin A1 - Bargheer, Matias T1 - Localized excited charge carriers generate ultrafast inhomogeneous strain in the multiferroic BiFeO3 JF - Physical review letters N2 - We apply ultrafast x-ray diffraction with femtosecond temporal resolution to monitor the lattice dynamics in a thin film of multiferroic BiFeO3 after above-band-gap photoexcitation. The sound-velocity limited evolution of the observed lattice strains indicates a quasi-instantaneous photoinduced stress which decays on a nanosecond time scale. This stress exhibits an inhomogeneous spatial profile evidenced by the broadening of the Bragg peak. These new data require substantial modification of existing models of photogenerated stresses in BiFeO3: the relevant excited charge carriers must remain localized to be consistent with the data. Y1 - 2014 U6 - https://doi.org/10.1103/PhysRevLett.112.097602 SN - 0031-9007 SN - 1079-7114 VL - 112 IS - 9 PB - American Physical Society CY - College Park ER -