title: Large temperature dependence of the number of carriers in co-doped BaFe(2)As(2).
abstract: Using angle-resolved photoemission spectroscopy, we study the evolution of the number of carriers in Ba(Fe(1-x)Co(x))(2)As(2) as a function of Co content and temperature. We show that there is a k-dependent energy shift compared to density functional calculations, which is large below 100 K at low Co contents and reduces the volume of hole and electron pockets by a factor 2. This k shift becomes negligible at high Co content and could be due to interband charge or spin fluctuations. We further reveal that the bands shift with temperature, changing significantly the number of carriers they contain (up to 50%). We explain this evolution by thermal excitations of carriers among the narrow bands, possibly combined with a temperature evolution of the k-dependent fluctuations.
authors.affiliation: Laboratoire de Physique des Solides, Université Paris-Sud, UMR 8502, Bâtiment 510, 91405 Orsay, France.
authors.forename: V
authors.initials: V
authors.lastname: Brouet
authors.forename: Ping-Hui
authors.initials: PH
authors.lastname: Lin
authors.forename: Y
authors.initials: Y
authors.lastname: Texier
authors.forename: J
authors.initials: J
authors.lastname: Bobroff
authors.forename: A
authors.initials: A
authors.lastname: Taleb-Ibrahimi
authors.forename: P
authors.initials: P
authors.lastname: Le Fèvre
authors.forename: F
authors.initials: F
authors.lastname: Bertran
authors.forename: M
authors.initials: M
authors.lastname: Casula
authors.forename: P
authors.initials: P
authors.lastname: Werner
authors.forename: S
authors.initials: S
authors.lastname: Biermann
authors.forename: F
authors.initials: F
authors.lastname: Rullier-Albenque
authors.forename: A
authors.initials: A
authors.lastname: Forget
authors.forename: D
authors.initials: D
authors.lastname: Colson