Publication Details

Zhang, Z., Jin, Z., Pan, Q., Xu, Y., Lin, X., Ma, G. & Cheng, Z. (2014). Temperature dependent photoexcited carrier dynamics in multiferroic BiFeO3 film: a hidden phase transition. Applied Physics Letters, 104 (15), 151902-1-151902-5.


The ultrafast carrier dynamics of the multiferroic BiFeO3 film in a broad temperature range is investigated using optical pump-probe spectroscopy. The photoexcited electrons release their energy with optical phonons emission through electron-phonon coupling in about 1 ps. The following intermediate process is identified as dynamical spin-lattice coupling in several picoseconds. Furthermore, the peak values of the optical reflectivity and the time constants of carrier relaxation channels show significant changes while the temperature varies from 137.5 K to around 195 K, this aligns with the previously reported hidden phase transition. Our study demonstrates that ultrafast spectroscopy is a sensitive method to look into the dynamical interactions among the on-site high-energy electrons accumulated in the p conduction band of Bi, coherent optical phonon, as well as the spin degree of freedom. These features play crucial roles in the characterization of phase transitions.

Grant Number




Link to publisher version (DOI)