TY  - JOUR
AU  - Bertinshaw, J.
AU  - Krautloher, Maximilian
AU  - Suzuki, H.
AU  - Takahashi, Hiroto
AU  - Ivanov, A.
AU  - Yavaş, H.
AU  - Kim, Bumjoon
AU  - Gretarsson, H.
AU  - Keimer, B.
TI  - Spin and charge excitations in the correlated multiband metal Ca<sub>3</sub>Ru<sub>2</sub>O<sub>7</sub>
JO  - Physical review / B
VL  - 103
IS  - 8
SN  - 2469-9950
CY  - Woodbury, NY
PB  - Inst.
M1  - PUBDB-2021-00998
SP  - 085108
PY  - 2021
AB  - We use Ru L<sub>3</sub>-edge resonant inelastic x-ray scattering to study the full range of excitations in Ca<sub>3</sub>Ru<sub>2</sub>O<sub>7</sub> from meV-scale magnetic dynamics through to the eV-scale interband transitions. This bilayer 4d-electron correlated metal expresses a rich phase diagram, displaying long-range magnetic order below 56 K followed by a concomitant structural, magnetic, and electronic transition at 48 K. In the low-temperature phase, we observe a magnetic excitation with a bandwidth of ∼30 meV and a gap of ∼8 meV at the zone center, in excellent agreement with inelastic neutron scattering data. The dispersion can be modeled using a Heisenberg Hamiltonian for a bilayer S=1 system with single-ion anisotropy terms. At a higher energy loss, dd-type excitations show heavy damping in the presence of itinerant electrons, giving rise to a fluorescencelike signal appearing between the t<sub>2g</sub> and e<sub>g</sub> bands. At the same time, we observe a resonance originating from localized t<sub>2g</sub> excitations, in analogy to the structurally related Mott insulator Ca<sub>2</sub>RuO<sub>4</sub>. But whereas Ca<sub>2</sub>RuO<sub>4</sub> shows sharp separate spin-orbit excitations and Hund's-rule driven spin-state transitions, here we identify only a single broad asymmetric feature. These results indicate that local intraionic interactions underlie the correlated physics in Ca<sub>3</sub>Ru<sub>2</sub>O<sub>7</sub>, even as the excitations become strongly mixed in the presence of itinerant electrons. 
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000615717100002
DO  - DOI:10.1103/PhysRevB.103.085108
UR  - https://bib-pubdb1.desy.de/record/455234
ER  -