Author/Authors :
Fِrst، نويسنده , , M. and Mankowsky، نويسنده , , R. and Bromberger، نويسنده , , H. and Fritz، نويسنده , , D.M. and Lemke، نويسنده , , H. and Zhu، نويسنده , , D. and Chollet، نويسنده , , M. and Tomioka، نويسنده , , Y. and Tokura، نويسنده , , Ruth Y. Andia-Merlin، نويسنده , , R. and Hill، نويسنده , , J.P. and Johnson، نويسنده , , S.L. and Cavalleri، نويسنده , , A.، نويسنده ,
Abstract :
The nonlinear lattice dynamics of La0.7Sr0.3MnO3, as initiated by strong mid-infrared femtosecond pulses made resonant with a specific lattice vibration, are measured with ultrafast X-ray diffraction at the LCLS free electron laser. Our experiments show that large amplitude excitation of an infrared-active stretching mode leads also to a displacive motion along the coordinate of a second, anharmonically coupled, Raman mode. This rectification of the vibrational field is described within the framework of the Ionic Raman Scattering theory and explains how direct lattice excitation in the nonlinear regime can induce a structural phase transition.
Keywords :
A. Correlated electron systems , D. Nonlinear phononics , D. Ionic Raman Scattering , E. Time-resolved hard X-ray diffraction
