Spin and orbital excitations through the metal-to-insulator transition in 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Cd</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Os</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:mrow></mml:math>
 probed with high-resolution resonant inelastic x-ray scattering

Vale, J. G.; Calder, Stuart; Bogdanov, Nikolay A.; Donnerer, C.; Sala, M. Moretti; Davies, N. R.; Mandrus, David; Brink, Jeroen van den; Christianson, A. D.; McMorrow, D. F.

doi:10.1103/physrevb.101.014441

Cited by 5 publications

(3 citation statements)

References 48 publications

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“…In these theoretical studies, a sizeable single-ion anisotropy (SIA) is found along the local [111] axis, and there is even the trigonal distortion of the OsO 6 octahedron. The large SIA is experimentally confirmed, too [4,12,13]. A spin Hamiltonian with a large anisotropy was used to analyze the multiple spin-flip excitations observed in RIXS experiments [4,12] and the two-magnon continuum from Raman spectroscopy [13].…”

Section: Introductionmentioning

confidence: 96%

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Spin-orbit coupling effects on spin-phonon coupling in Cd2Os2O7

et al. 2020

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Spin-orbit coupling (SOC) is essential in understanding the properties of 5d transition metal compounds, whose SOC value is large and almost comparable to other key parameters. Over the past few years, there have been numerous studies on the SOC-driven effects of the electronic bands, magnetism, and spin-orbit entanglement for those materials with a large SOC. However, it is less studied and remains an unsolved problem in how the SOC affects the lattice dynamics. We, therefore, measured the phonon spectra of 5d pyrochlore Cd 2 Os 2 O 7 over the full Brillouin zone to address the question by using inelastic x-ray scattering (IXS). Our main finding is a visible mode-dependence in the phonon spectra, measured across the metal-insulator transition at 227 K. We examined the SOC strength dependence of the lattice dynamics and its spin-phonon (SP) coupling, with first-principle calculations. Our experimental data taken at 100 K are in good agreement with the theoretical results obtained with the optimized U = 2.0 eV with SOC. By scaling the SOC strength and the U value in the DFT calculations, we demonstrate that SOC is more relevant than U to explaining the observed mode-dependent phonon energy shifts with temperature. Furthermore, the temperature dependence of the phonon energy can be effectively described by scaling SOC. Our work provides clear evidence of SOC producing a non-negligible and essential effect on the lattice dynamics of Cd 2 Os 2 O 7 and its SP coupling.

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Section: Introductionmentioning

confidence: 96%

“…The large SIA is experimentally confirmed, too [4,12,13]. A spin Hamiltonian with a large anisotropy was used to analyze the multiple spin-flip excitations observed in RIXS experiments [4,12] and the two-magnon continuum from Raman spectroscopy [13]. The spin Hamiltonian used for the proceeding analysis can be written as…”

Section: Introductionmentioning

confidence: 99%

Spin-orbit coupling effects on spin-phonon coupling in Cd2Os2O7

et al. 2020

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“…The driving force has been ascribed to electron correlations as well as SOIs [15,25,26]. Numerous recent experiments provide evidence for this mechanism, as well as additional intriguing phenomena such as strong spin-phonon couplings and coupled spin-charge-phonon fluctuations [27][28][29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Pyrochlore oxide Hg₂Os₂O₇ on verge of metal–insulator boundary

Kataoka¹,

Hirai²,

Koda³

et al. 2022

J. Phys.: Condens. Matter

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Semimetallic osmium pyrochlore oxide Cd2Os2O7 undergoes a magnetic transition to an all-in-all-out (AIAO)-type order at 227 K, followed by a crossover to an AIAO insulator at around 210 K. Here, we studied the isostructural and isoelectronic compound Hg2Os2O7 through thermodynamic measurements, µSR spectroscopy and neutron diffraction experiments. A similar magnetic transition, probably to an AIAO-type order, was observed at 88 K, while the resistivity showed a decrease at the transition and remained metallic down to 2 K. Thus, the ground state of Hg2Os2O7 is most likely an AIAO semimetal, which is analogous to the intermediate-temperature state of Cd2Os2O7. Hg2Os2O7 exists on the verge of the metal–insulator boundary on the metal side and provides an excellent platform for studying the electronic instability of 5d electrons with moderate electron correlations and strong spin–orbit interactions.

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