Dichotomy in ultrafast atomic dynamics as direct evidence of polaron formation in manganites

• DOI: 10.1038/npjquantmats.2016.26
• Publication Date: 2016-11-25T11:02:11Z
• Authors: Junjie Li; Wei-Guo Yin; Lijun Wu; Pengfei Zhu; Tatianna Konstant...; Jing Tao; Junjie Yang; Sang-Wook Cheong; Fabrizio Carbone; James A Misewich; John P Hill; Xijie Wang; Robert J Cava; Yimei Zhu
• Keywords: Photoexcitation; Lattice (music)

Abstract Polaron transport, in which electron motion is strongly coupled to the underlying lattice deformation or phonons, crucial for understanding electrical and optical conductivities many solids. However, little known experimentally about dynamics of individual phonon modes during polaron motion. It remains elusive whether polarons have a key role materials with strong electronic correlations. Here we report use new experimental technique, ultrafast MeV-electron diffraction, quantify both atomic motions correlated LaSr 2 Mn O 7 . Using photoexcitation set system motion, find that Jahn-Teller-like O, 4+ La/Sr displacements dominate response exhibit dichotomy behaviour—overshoot-and-recovery one sublattice versus normal behaviour other. This dichotomy, attributed slow relaxation, proves transport process doped manganites. Our technique promises be applicable specifying nature electron–phonon coupling complex materials.