title: Extremely high electron mobility in a phonon-glass semimetal.
abstract: The electron mobility is one of the key parameters that characterize the charge-carrier transport properties of materials, as exemplified by the quantum Hall effect as well as high-efficiency thermoelectric and solar energy conversions. For thermoelectric applications, introduction of chemical disorder is an important strategy for reducing the phonon-mediated thermal conduction, but is usually accompanied by mobility degradation. Here, we show a multilayered semimetal β-CuAgSe overcoming such a trade-off between disorder and mobility. The polycrystalline ingot shows a giant positive magnetoresistance and Shubnikov de Haas oscillations, indicative of a high-mobility small electron pocket derived from the Ag s-electron band. Ni doping, which introduces chemical and lattice disorder, further enhances the electron mobility up to 90,000 cm(2) V(-1) s(-1) at 10 K, leading not only to a larger magnetoresistance but also a better thermoelectric figure of merit. This Ag-based layered semimetal with a glassy lattice is a new type of promising thermoelectric material suitable for chemical engineering.
authors.affiliation: Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Hongo, Tokyo, Japan. ishiwata@ap.t.u-tokyo.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Ishiwata
authors.forename: Y
authors.initials: Y
authors.lastname: Shiomi
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: M S
authors.initials: MS
authors.lastname: Bahramy
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: M
authors.initials: M
authors.lastname: Uchida
authors.forename: R
authors.initials: R
authors.lastname: Arita
authors.forename: Y
authors.initials: Y
authors.lastname: Taguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Tokura