Ultrafast structural phase transition driven by photoinduced melting of charge and orbital order.
We use femtosecond x-ray diffraction to probe directly the structural dynamics of a charge ordered and orbitally ordered thin film of La0.42Ca0.58MnO3 initiated by an ultrafast optical pulse. At low excitation fluences we observe the displacive excitation of a coherent optical A(g) phonon. Under high excitation conditions we observe a complete phase transition within 1 ps via the disappearance of a superlattice reflection. The initial step of the phase transition occurs on a time scale significantly faster than the 200 fs time resolution of our experiment.
Beaud
P
P
Swiss Light Source, Paul Scherrer Institut, 5232 Villigen PSI, Switzerland. paul.beaud@psi.ch
Johnson
S L
SL
Vorobeva
E
E
Staub
U
U
De Souza
R A
RA
Milne
C J
CJ
Jia
Q X
QX
Ingold
G
G