title: Convergence of multi-valley bands as the electronic origin of high thermoelectric performance in CoSb3 skutterudites.
abstract: Filled skutterudites R(x)Co4Sb12 are excellent n-type thermoelectric materials owing to their high electronic mobility and high effective mass, combined with low thermal conductivity associated with the addition of filler atoms into the void site. The favourable electronic band structure in n-type CoSb3 is typically attributed to threefold degeneracy at the conduction band minimum accompanied by linear band behaviour at higher carrier concentrations, which is thought to be related to the increase in effective mass as the doping level increases. Using combined experimental and computational studies, we show instead that a secondary conduction band with 12 conducting carrier pockets (which converges with the primary band at high temperatures) is responsible for the extraordinary thermoelectric performance of n-type CoSb3 skutterudites. A theoretical explanation is also provided as to why the linear (or Kane-type) band feature is not beneficial for thermoelectrics.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.|Materials Science, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Yinglu
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Zachary M
authors.initials: ZM
authors.lastname: Gibbs
authors.affiliation: Department of Physics, University of North Texas, Denton, Texas 76203, USA.|Department of Mechanical Engineering and Materials Science, Physics and Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Agapito
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.|Materials Science, California Institute of Technology, Pasadena, California 91125, USA.|State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, Hubei 430070, China.
authors.forename: Guodong
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.|Materials Science, California Institute of Technology, Pasadena, California 91125, USA.|Materials Research Center, Samsung Advanced Institute of Technology, Samsung Electronics, Suwon 443-803, South Korea.
authors.forename: Hyun-Sik
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Physics, University of North Texas, Denton, Texas 76203, USA.
authors.forename: Marco Buongiorno
authors.initials: MB
authors.lastname: Nardelli
authors.affiliation: Department of Mechanical Engineering and Materials Science, Physics and Chemistry, Duke University, Durham, North Carolina 27708, USA.
authors.forename: Stefano
authors.initials: S
authors.lastname: Curtarolo
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.|Materials Science, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: G Jeffrey
authors.initials: GJ
authors.lastname: Snyder