title: Synthesis, Crystal Structure, Theoretical, and Resistivity Study of BaUSe3.
abstract: The black-colored compound BaUSe3 has been synthesized at 1173 K by a stoichiometric reaction of the elements in a CsCl flux. BaUSe3 crystallizes in the GdFeO3 structure type. There is no change in structure between 100 and 298 K. The U atoms in this structure are octahedrally connected to six Se atoms. Each octahedral unit shares all six corners with neighboring octahedra, forming a three-dimensional network. BaUSe3 can be charge balanced as Ba(2+)U(4+)(Se(2-))3. DFT electronic structure calculations found BaUSe3 to be antiferromagnetic in its ground state and to be a semiconductor with a band gap of 2.5 eV. The band gap is inconsistent with the black color of the material and with the small activation energy of 0.12(1) eV obtained from resistivity measurements. A UV-vis spectrum indicated that there was no band gap above 1 eV. It is possible that, for BaUSe3, intrinsic and extrinsic impurities from the flux create midgap states that lead to the experimentally measured narrow optical gap. More likely, BaUSe3 presents a challenge to DFT calculations as applied to 5f materials.
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208-3113, United States.
authors.forename: Jai
authors.initials: J
authors.lastname: Prakash
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208-3113, United States.
authors.forename: Maria S
authors.initials: MS
authors.lastname: Tarasenko
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208-3113, United States.|ICSM, UMR 5257 CEA/CNRS/UM2/ENSCM , Site de Marcoule - Bât. 426, BP 17171, 30207 Bagnols-sur-Cèze cedex, France.
authors.forename: Adel
authors.initials: A
authors.lastname: Mesbah
authors.affiliation: Laboratoire de Cristallographie, Résonance Magnétique et Modélisations (CRM2, UMR CNRS 7036), Institut Jean Barriol, Université de Lorraine , BP 239, Boulevard des Aiguillettes, 54506 Vandoeuvre-lès-Nancy, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Lebègue
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208-3113, United States.
authors.forename: Christos D
authors.initials: CD
authors.lastname: Malliakas
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, IL 60208-3113, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: Ibers