title: Experimental Evidence for Static Charge Density Waves in Iron Oxypnictides.
abstract: In this Letter we report high-resolution synchrotron x-ray powder diffraction and transmission electron microscope analysis of Mn-substituted LaFeAsO samples, demonstrating that a static incommensurate modulated structure develops across the low-temperature orthorhombic phase, whose modulation wave vector depends on the Mn content. The incommensurate structural distortion is likely originating from a charge-density-wave instability, a periodic modulation of the density of conduction electrons associated with a modulation of the atomic positions. Our results add a new component in the physics of Fe-based superconductors, indicating that the density wave ordering is charge driven.
authors.affiliation: SPIN-CNR, C.so Perrone 24, I- 16152 Genova-Italy.
authors.forename: A
authors.initials: A
authors.lastname: Martinelli
authors.affiliation: SPIN-CNR, C.so Perrone 24, I- 16152 Genova-Italy.|Department of Chemistry and Industrial Chemistry, Università di Genova, Via Dodecaneso 31, I-16146 Genova, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Manfrinetti
authors.affiliation: SPIN-CNR, C.so Perrone 24, I- 16152 Genova-Italy.|Department of Chemistry and Industrial Chemistry, Università di Genova, Via Dodecaneso 31, I-16146 Genova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Provino
authors.affiliation: Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900 Jeddah, Saudi Arabia.
authors.forename: A
authors.initials: A
authors.lastname: Genovese
authors.affiliation: SPIN-CNR, C.so Perrone 24, I- 16152 Genova-Italy.|Department of Physics, Università di Genova, Via Dodecaneso 33, I-16146 Genova, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Caglieris
authors.affiliation: SPIN-CNR, C.so Perrone 24, I- 16152 Genova-Italy.
authors.forename: G
authors.initials: G
authors.lastname: Lamura
authors.affiliation: Institute Laue-Langevin, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9-France.
authors.forename: C
authors.initials: C
authors.lastname: Ritter
authors.affiliation: SPIN-CNR, C.so Perrone 24, I- 16152 Genova-Italy.|Department of Physics, Università di Genova, Via Dodecaneso 33, I-16146 Genova, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Putti