title: The intrinsic disorder related alloy scattering in ZrNiSn half-Heusler thermoelectric materials.
abstract: The intrinsic structural disorder dramatically affects the thermal and electronic transport in semiconductors. Although normally considered an ordered compound, the half-Heusler ZrNiSn displays many transport characteristics of a disordered alloy. Similar to the (Zr,Hf)NiSn based solid solutions, the unsubstituted ZrNiSn compound also exhibits charge transport dominated by alloy scattering, as demonstrated in this work. The unexpected charge transport, even in ZrNiSn which is normally considered fully ordered, can be explained by the Ni partially filling interstitial sites in this half-Heusler system. The influence of the disordering and defects in crystal structure on the electron transport process has also been quantitatively analyzed in ZrNiSn1-xSbx with carrier concentration nH ranging from 5.0 × 10(19) to 2.3 × 10(21) cm(-3) by changing Sb dopant content. The optimized carrier concentration nH ≈ 3-4 × 10(20) cm(-2) results in ZT ≈ 0.8 at 875K. This work suggests that MNiSn (M = Hf, Zr, Ti) and perhaps most other half-Heusler thermoelectric materials should be considered highly disordered especially when trying to understand the electronic and phonon structure and transport features.
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Hanhui
authors.initials: H
authors.lastname: Xie
authors.affiliation: Department of Materials Science, California Institute of Technology, Pasadena, CA 91125, (USA).
authors.forename: Heng
authors.initials: H
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Chenguang
authors.initials: C
authors.lastname: Fu
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Yintu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Materials Science, California Institute of Technology, Pasadena, CA 91125, (USA).
authors.forename: G Jeffrey
authors.initials: GJ
authors.lastname: Snyder
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Xinbing
authors.initials: X
authors.lastname: Zhao
authors.affiliation: 1] State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China [2] Cyrus Tang Center for Sensor Materials and Applications, Zhejiang University, Hangzhou, 310027, China.
authors.forename: Tiejun
authors.initials: T
authors.lastname: Zhu