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TT: Fachverband Tiefe Temperaturen

TT 7: Focused Session: Resonant Inelastic X-ray Scattering on Magnetic Excitations

TT 7.5: Topical Talk

Montag, 26. März 2012, 18:00–18:40, H 0104

Fractionalization of electronic degrees of freedom in low-dimensional cuprates — •Justine Schlappa^1,2, Thorsten Schmitt¹, Kejin Zhou¹, Krzysztof Wohlfeld³, Jeroen van den Brink³, Maurits Haverkort⁴, Martin Mourigal⁵, and Henrik Rønnow⁵ — ¹Paul Scherrer Institut, Swiss Light Source, CH-5232 Villigen PSI, Switzerland — ²Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, D-12489 Berlin, Germany — ³Leibniz Institute for Solid State and Materials Research IFW Dresden, D-01171 Dresden, Germany — ⁴Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany — ⁵Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

Quantum effects become important, when the space symmetry is lowered. In the extreme case of one dimension the fundamental degrees of freedom of the electron can break up into separate quasi-particles, carrying either one of the spin, charge or orbital degrees of freedom. Here we report the study of elementary excitations in the quasi 1D cuprate Sr₂CuO₃, using high-resolution Resonant Inelastic X-ray Scattering. In the low-energy range the fractionalization of magnons into two-spinons and higher order excitations is observed, as previously reported from neutron scattering [1]. At higher energies we observe the deconfinement of spin and orbital degrees of freedom [2]. This phenomenon allows for the first time a direct observation of strongly dispersive orbital excitations (orbitons).
A.C. Walters et al., Nature Physics 5, 867 (2009).
J. Schlappa, T. Schmitt et al., submitted