title: Improvement of thermoelectric properties and their correlations with electron effective mass in Cu1.98SxSe1-x.
abstract: Sulphur doping effects on the crystal structures, thermoelectric properties, density-of-states, and effective mass in Cu1.98SxSe1-xwere studied based on the electrical and thermal transport property measurements, and first-principles calculations. The X-ray diffraction patterns and Rietveld refinements indicate that room temperature Cu1.98SxSe1-x(x = 0, 0.02, 0.08, 0.16) and Cu1.98SxSe1-x(x = 0.8, 0.9, 1.0) have the same crystal structure as monoclinic-Cu2Se and orthorhombic-Cu2S, respectively. Sulphur doping can greatly enhance zT values when x is in the range of 0.8≤ × ≤1.0. Furthermore, all doped samples show stable thermoelectric compatibility factors over a broad temperature range from 700 to 1000 K, which could greatly benefit their practical applications. First-principles calculations indicate that both the electron density-of-sates and the effective mass for all the compounds exhibit non-monotonic sulphur doping dependence. It is concluded that the overall thermoelectric performance of the Cu1.98SxSe1-xsystem is mainly correlated with the electron effective mass and the density-of-states.
authors.affiliation: School of Physics, Shandong University, Jinan, 250100, P.R. China.|Spintronic and Electronic Materials Group, Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, 2500, Australia.
authors.forename: Lanling
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Spintronic and Electronic Materials Group, Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, 2500, Australia.
authors.forename: Frank Yun
authors.initials: FY
authors.lastname: Fei
authors.affiliation: Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Shandong University, Jinan, 250061, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: School of Physics, Shandong University, Jinan, 250100, P.R. China.
authors.forename: Funing
authors.initials: F
authors.lastname: Wang
authors.affiliation: School of Physics, Shandong University, Jinan, 250100, P.R. China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Wang
authors.affiliation: School of Physics, Shandong University, Jinan, 250100, P.R. China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Li
authors.affiliation: Institute for Crystal Materials, Shandong University, Jinan, 250100, P. R. China.
authors.forename: Jiyang
authors.initials: J
authors.lastname: Wang
authors.affiliation: Spintronic and Electronic Materials Group, Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, 2500, Australia.
authors.forename: Zhenxiang
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: Spintronic and Electronic Materials Group, Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, 2500, Australia.
authors.forename: Shixue
authors.initials: S
authors.lastname: Dou
authors.affiliation: Spintronic and Electronic Materials Group, Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, North Wollongong, 2500, Australia.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang