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Low Electron Scattering Potentials in High Performance Mg 2 Si 0.45 Sn 0.55 Based Thermoelectric Solid Solutions with Band Convergence
Author(s) -
Liu Xiaohua,
Zhu Tiejun,
Wang Heng,
Hu Lipeng,
Xie Hanhui,
Jiang Guangyu,
Snyder G. Jeffrey,
Zhao Xinbing
Publication year - 2013
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201300174
Subject(s) - thermoelectric effect , materials science , thermoelectric materials , phonon scattering , scattering , effective mass (spring–mass system) , condensed matter physics , solid solution , electron mobility , alloy , seebeck coefficient , electronic band structure , charge carrier , carrier scattering , thermal conductivity , optoelectronics , thermodynamics , metallurgy , composite material , physics , optics , quantum mechanics
Understanding the electron and phonon transport characteristics is crucial for designing and developing high performance thermoelectric materials. Weak scattering effects on charge carriers, characterized by deformation potential and alloy scattering potential, are favorable for thermoelectric solid solutions to enable high carrier mobility and thereby promising thermoelectric performance. Mg 2 (Si,Sn) solid solutions have attracted much attention due to their low cost and environmental compatibility. Usually, their high thermoelectric performance with ZT ∼ 1 is ascribed to the band convergence and reduced lattice thermal conductivity caused by alloying. In this work, both a low deformation potential Ξ = 13 eV and a low alloy scattering potential U = 0.7 eV are found for the thermoelectric alloys by characterizing and modeling of thermoelectric transport properties. The band convergence is also verified by the increased density‐of‐states effective mass. It is proposed that, in addition to band convergence and reduced lattice thermal conductivity, the low deformation potential and alloy scattering potential are additional intrinsic features that contribute to the high thermoelectric performance of the solid solutions.