Neutron scattering studies on ionic diffusion behaviors of superionic α-Cu2−δ Se
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Date
2022-10-10
Journal Title
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Publisher
AIP Publishing
Abstract
We present studies on crystal structure and ionic diffusion behaviors of superionic Cu2−δ Se (δ = 0, 0.04, and 0.2) by utilizing neutron powder diffraction and quasi-elastic neutron scattering. In the superionic phase, the structural model with Cu ions occupying the Wyckoff sites of 8c and 32f provides the best description of the structure. As the content of Cu increasing in Cu2−δ Se, the Cu occupancy increases on the 32f site but decreases on the 8c site. Fitting to the quasi-elastic neutron scattering spectra reveals two diffusion modes: the localized diffusion between the 8c and 32f sites and the long-range diffusion between the adjacent 8c sites using the 32f site as a bypass. Between 430 and 650 K, we measured that the compound with more Cu content exhibits a larger long-range diffusion coefficient. Temperature in this range does not affect the long-range diffusion process obviously. Our results suggest the two diffusion modes cooperative and, thus, provide a microscopic understanding of the ionic diffusion of the Cu ions in superionic Cu2−δ Se. © 2024 AIP Publishing LLC
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Keywords
Neutrons, Selenium, Copper, Crystal structure, Temperature range, Scattering, Diffraction, Diffusion, Thermoelectric materials, Spectra
Citation
Li, L., Liu, H., Avdeev, M., Yu, D., Danilkin, S., & Wang, M. (2022). Neutron scattering studies on ionic diffusion behaviors of superionic α-Cu2−δ Se. Applied Physics Letters, 121(15), 151901. doi:10.1063/5.0107238