title: Orbital control of effective dimensionality: from spin-orbital fractionalization to confinement in the anisotropic ladder system CaCu(2)O(3).
abstract: Fractionalization of an electronic quasiparticle into spin, charge, and orbital parts is a fundamental and characteristic property of interacting electrons in one dimension. However, real materials are never strictly one dimensional and the fractionalization phenomena are hard to observe. Here we studied the spin and orbital excitations of the anisotropic ladder material CaCu_{2}O_{3}, whose electronic structure is not one dimensional. Combining high-resolution resonant inelastic x-ray scattering experiments with theoretical model calculations, we show that (i) spin-orbital fractionalization occurs in CaCu_{2}O_{3} along the leg direction x through the xz orbital channel as in a 1D system, and (ii) no fractionalization is observed for the xy orbital, which extends in both leg and rung direction, contrary to a 1D system. We conclude that the directional character of the orbital hopping can select different degrees of dimensionality. Using additional model calculations, we show that spin-orbital separation is generally far more robust than the spin-charge separation. This is not only due to the already mentioned selection realized by the orbital hopping, but also due to the fact that spinons are faster than the orbitons.
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Swiss Light Source, Paul Scherrer Insitute, CH-5232 Villigen PSI, Switzerland.|National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors: Valentina
authors: V
authors: Bisogni
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Stanford Institute for Materials and Energy Sciences, SLAC National Laboratory and Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025, USA.|Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Pasteura 5, PL-02093 Warsaw, Poland.
authors: Krzysztof
authors: K
authors: Wohlfeld
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors: Satoshi
authors: S
authors: Nishimoto
authors: Swiss Light Source, Paul Scherrer Insitute, CH-5232 Villigen PSI, Switzerland.|Department of Physics, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
authors: Claude
authors: C
authors: Monney
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors: Jan
authors: J
authors: Trinckauf
authors: Swiss Light Source, Paul Scherrer Insitute, CH-5232 Villigen PSI, Switzerland.|Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, United Kingdom.
authors: Kejin
authors: K
authors: Zhou
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors: Roberto
authors: R
authors: Kraus
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors: Klaus
authors: K
authors: Koepernik
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi-630 003, Tamilnadu, India.
authors: Chinnathambi
authors: C
authors: Sekar
authors: Swiss Light Source, Paul Scherrer Insitute, CH-5232 Villigen PSI, Switzerland.
authors: Vladimir
authors: V
authors: Strocov
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Department of Physics, Technical University Dresden, D-1062 Dresden, Germany.
authors: Bernd
authors: B
authors: Büchner
authors: Swiss Light Source, Paul Scherrer Insitute, CH-5232 Villigen PSI, Switzerland.
authors: Thorsten
authors: T
authors: Schmitt
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Department of Physics, Technical University Dresden, D-1062 Dresden, Germany.
authors: Jeroen
authors: J
authors: van den Brink
authors: IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors: Jochen
authors: J
authors: Geck
mesh_terms: D016880:Anisotropy; D017610:Calcium Compounds / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004583:Electrons; D008962:Models, Theoretical; D010087:Oxides / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D010087:Oxides; D003300:Copper