title: Direct phase-sensitive identification of a d-form factor density wave in underdoped cuprates.
abstract: The identity of the fundamental broken symmetry (if any) in the underdoped cuprates is unresolved. However, evidence has been accumulating that this state may be an unconventional density wave. Here we carry out site-specific measurements within each CuO2 unit cell, segregating the results into three separate electronic structure images containing only the Cu sites [Cu(r)] and only the x/y axis O sites [Ox(r) and O(y)(r)]. Phase-resolved Fourier analysis reveals directly that the modulations in the O(x)(r) and O(y)(r) sublattice images consistently exhibit a relative phase of π. We confirm this discovery on two highly distinct cuprate compounds, ruling out tunnel matrix-element and materials-specific systematics. These observations demonstrate by direct sublattice phase-resolved visualization that the density wave found in underdoped cuprates consists of modulations of the intraunit-cell states that exhibit a predominantly d-symmetry form factor.
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan;
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;
authors.forename: Mohammad H
authors.initials: MH
authors.lastname: Hamidian
authors.affiliation: Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;School of Physics and Astronomy, University of St. Andrews, Fife KY16 9SS, Scotland;
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Edkins
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;
authors.forename: Chung Koo
authors.initials: CK
authors.lastname: Kim
authors.affiliation: RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan;
authors.forename: Yuhki
authors.initials: Y
authors.lastname: Kohsaka
authors.affiliation: Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Kanagawa 226-8503, Japan;
authors.forename: Masaki
authors.initials: M
authors.lastname: Azuma
authors.affiliation: Institute for Integrated Cell-Material Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan;
authors.forename: Mikio
authors.initials: M
authors.lastname: Takano
authors.affiliation: Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan;RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan;Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany;
authors.forename: Hidenori
authors.initials: H
authors.lastname: Takagi
authors.affiliation: Nanoelectronics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8568, Japan;
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Eisaki
authors.affiliation: Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan;
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Uchida
authors.affiliation: Department of Physics, Harvard University, Cambridge, MA 02138;
authors.forename: Andrea
authors.initials: A
authors.lastname: Allais
authors.affiliation: Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;Department of Physics and Astronomy, Binghamton University, Binghamton, NY 13902; and.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lawler
authors.affiliation: Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;
authors.forename: Eun-Ah
authors.initials: EA
authors.lastname: Kim
authors.affiliation: Department of Physics, Harvard University, Cambridge, MA 02138;Perimeter Institute for Theoretical Physics, Waterloo, ON, Canada N2L 2Y5.
authors.forename: Subir
authors.initials: S
authors.lastname: Sachdev
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;School of Physics and Astronomy, University of St. Andrews, Fife KY16 9SS, Scotland; jcseamusdavis@gmail.com.
authors.forename: J C Séamus
authors.initials: JC
authors.lastname: Davis
keywords: CuO2 pseudogap; broken symmetry; density-wave form factor