posted on 2021-02-24, 20:15authored byZhen Wu, Yuanyuan Zhang, Rongrong Hu, Meizhen Jiang, Pan Liang, Qing Yang, Li Deng, Tianqing Jia, Zhenrong Sun, Donghai Feng
Electron spin dynamics in CdSe quantum
dots with hole acceptors
are investigated by time-resolved ellipticity spectroscopy. Two types
of hole acceptors, Li[Et3BH] and 1-octanethiol, result
in distinctly different electron spin dynamics. The differences include
electron g factors, spin dephasing/relaxation times,
and mechanisms. In CdSe quantum dots with Li[Et3BH], the
electron spin dephasing and relaxation are dominated by electron–nuclear
hyperfine interactions in zero and weak magnetic fields. In contrast,
hyperfine interactions, electron carrier lifetimes, and exchange interactions
between electrons and holes or surface dangling bond spins control
the electron spin dynamics in CdSe quantum dots with 1-octanethiol.
Inhomogeneous dephasing limits the spin coherence time in larger transverse
magnetic fields for both hole acceptor cases, but with distinct different g-factor inhomogeneity. These findings manifest that surface
conditions play an important role in the spin dynamics and that thereby
the surface and its surroundings can be exploited to control the spin
in colloidal nanostructures.