title: Momentum-resolved evolution of the Kondo lattice into "hidden order" in URu2Si2.
abstract: We study, using high-resolution angle-resolved photoemission spectroscopy, the evolution of the electronic structure in URu2Si2 at the Γ, Z, and X high-symmetry points from the high-temperature Kondo-screened regime to the low-temperature hidden-order (HO) state. At all temperatures and symmetry points, we find structures resulting from the interaction between heavy and light bands related to the Kondo-lattice formation. At the X point, we directly measure a hybridization gap of 11 meV already open at temperatures above the ordered phase. Strikingly, we find that while the HO induces pronounced changes at Γ and Z, the hybridization gap at X does not change, indicating that the hidden-order parameter is anisotropic. Furthermore, at the Γ and Z points, we observe the opening of a gap in momentum in the HO state, and show that the associated electronic structure results from the hybridization of a light electron band with the Kondo-lattice bands characterizing the paramagnetic state.
authors.affiliation: Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: F L
authors.initials: FL
authors.lastname: Boariu
authors.affiliation: CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay Cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Bareille
authors.affiliation: Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Schwab
authors.affiliation: Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Nuber
authors.affiliation: Institut Néel, CNRS/UJF, B.P. 166, 38042 Grenoble Cedex 9, France.
authors.forename: P
authors.initials: P
authors.lastname: Lejay
authors.affiliation: MPA-CMMS, Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA.
authors.forename: T
authors.initials: T
authors.lastname: Durakiewicz
authors.affiliation: Lehrstuhl für Experimentelle Physik VII, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany and Karlsruher Institut für Technologie (KIT), Gemeinschaftslabor für Nanoanalythik, D-76021 Karlsruhe, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Reinert
authors.affiliation: CSNSM, Université Paris-Sud and CNRS/IN2P3, Bâtiments 104 et 108, 91405 Orsay Cedex, France.
authors.forename: A F
authors.initials: AF
authors.lastname: Santander-Syro