title: Anomalously low electronic thermal conductivity in metallic vanadium dioxide.
abstract: In electrically conductive solids, the Wiedemann-Franz law requires the electronic contribution to thermal conductivity to be proportional to electrical conductivity. Violations of the Wiedemann-Franz law are typically an indication of unconventional quasiparticle dynamics, such as inelastic scattering, or hydrodynamic collective motion of charge carriers, typically pronounced only at cryogenic temperatures. We report an order-of-magnitude breakdown of the Wiedemann-Franz law at high temperatures ranging from 240 to 340 kelvin in metallic vanadium dioxide in the vicinity of its metal-insulator transition. Different from previously established mechanisms, the unusually low electronic thermal conductivity is a signature of the absence of quasiparticles in a strongly correlated electron fluid where heat and charge diffuse independently.
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.|School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, South Korea.
authors.forename: Sangwook
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA.|Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, Innovis, 08-03, 138634 Singapore.
authors.forename: Kedar
authors.initials: K
authors.lastname: Hippalgaonkar
authors.affiliation: Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA.|The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: School of Aerospace Engineering and Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China.|Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Jiawang
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
authors.forename: Changhyun
authors.initials: C
authors.lastname: Ko
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
authors.forename: Joonki
authors.initials: J
authors.lastname: Suh
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.|Materials Sciences Division, LBNL, Berkeley, CA 94720, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Wang
authors.affiliation: The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Urban
authors.affiliation: Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA.|Materials Sciences Division, LBNL, Berkeley, CA 94720, USA.|Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Mechanical Engineering, University of California, Berkeley, CA 94720, USA.|Materials Sciences Division, LBNL, Berkeley, CA 94720, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Dames
authors.affiliation: Department of Physics, Stanford University, Stanford, CA 94305, USA.
authors.forename: Sean A
authors.initials: SA
authors.lastname: Hartnoll
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. wuj@berkeley.edu olivier.delaire@duke.edu.|Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA.
authors.forename: Olivier
authors.initials: O
authors.lastname: Delaire
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA 94720, USA. wuj@berkeley.edu olivier.delaire@duke.edu.|Materials Sciences Division, LBNL, Berkeley, CA 94720, USA.
authors.forename: Junqiao
authors.initials: J
authors.lastname: Wu