Spin-orbit-driven magnetic structure and excitation in the 5d pyrochlore Cd2Os2O7.
Much consideration has been given to the role of spin-orbit coupling (SOC) in 5d oxides, particularly on the formation of novel electronic states and manifested metal-insulator transitions (MITs). SOC plays a dominant role in 5d(5) iridates (Ir(4+)), undergoing MITs both concurrent (pyrochlores) and separated (perovskites) from the onset of magnetic order. However, the role of SOC for other 5d configurations is less clear. For example, 5d(3) (Os(5+)) systems are expected to have an orbital singlet with reduced effective SOC. The pyrochlore Cd2Os2O7 nonetheless exhibits a MIT entwined with magnetic order phenomenologically similar to pyrochlore iridates. Here, we resolve the magnetic structure in Cd2Os2O7 with neutron diffraction and then via resonant inelastic X-ray scattering determine the salient electronic and magnetic energy scales controlling the MIT. In particular, SOC plays a subtle role in creating the electronic ground state but drives the magnetic order and emergence of a multiple spin-flip magnetic excitation.
Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
S
S
Calder
London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
J G
JG
Vale
Institute for Theoretical Solid State Physics, IFW Dresden, Dresden D01171, Germany.
N A
NA
Bogdanov
Condensed matter physics and materials science department, Brookhaven National Laboratory, Upton, New York 11973, USA.|Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
X
X
Liu
London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
C
C
Donnerer
Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
M H
MH
Upton
Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
D
D
Casa
Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
A H
AH
Said
Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
M D
MD
Lumsden
Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.|Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Z
Z
Zhao
Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.|Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
J-Q
JQ
Yan
Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA.|Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
D
D
Mandrus
Institute for Theoretical Solid State Physics, IFW Dresden, Dresden D01171, Germany.|Institute for Theoretical Physics, Technische Universität Dresden, Dresden D01069, Germany.
S
S
Nishimoto
Institute for Theoretical Solid State Physics, IFW Dresden, Dresden D01171, Germany.|Institute for Theoretical Physics, Technische Universität Dresden, Dresden D01069, Germany.
J
J
van den Brink
Condensed matter physics and materials science department, Brookhaven National Laboratory, Upton, New York 11973, USA.
J P
JP
Hill
London Centre for Nanotechnology, University College London, London WC1H 0AH, UK.
D F
DF
McMorrow
Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.|Department of Physics &Astronomy, University of Tennessee, Knoxville, Tennessee 37996, USA.
A D
AD
Christianson