title: Size effect on the electron-phonon coupling in CuO nanocrystals.
abstract: CuO is the prototype compound of cuprate superconductors, so understanding its electronic structures will facilitate the study of the pairing mechanism and miscellaneous states of high-temperature superconductors. We prepared uniform CuO nanocrystals (7-100 nm) and studied their size-dependent Raman scattering spectra. The relative variation between the two-phonon scattering band (2B(g)) and the one-phonon band (B(g)) indicates a decreasing electron-phonon coupling with reducing size, which unveils the dominant Fröhlich electron-phonon coupling, as indicated by Devreese, but not the small polaron in CuO. Moreover, the anomalous enhancement of the multi-phonon band at a critical size and 1D structure at room temperature is attributable to an enhanced electron-phonon coupling accompanied by phonon-plasmon coupling, i.e., the 'plasphon' proposed by Alexandrov et al in 1981.
authors: Micro-Nano Technologies Research Center, Hunan University, Changsha 410082, People's Republic of China. Institute of Physics, Chinese Academy of Sciences, Beijing 100080, People's Republic of China.
authors: Haiming
authors: H
authors: Fan
authors: Bingsuo
authors: B
authors: Zou
authors: Yulong
authors: Y
authors: Liu
authors: Sishen
authors: S
authors: Xie