TY - JOUR
T1 - Crystal-field excitations and quadrupolar fluctuations of 4 f-electron systems studied by polarized light scattering
AU - Ye, M.
AU - Kung, H. H.
AU - Rosa, P. F.S.
AU - Rosenberg, E.
AU - Kim, J.
AU - Xu, X. H.
AU - Bauer, E. D.
AU - Fisk, Z.
AU - Fisher, I. R.
AU - Cheong, S. W.
AU - Blumberg, G.
N1 - Funding Information:
The spectroscopic work was supported by NSF DMR-1709161 and DMR-2105001. The sample preparation for CeB6 was supported by DOE Office of Basic Energy Sciences, Division of Materials Science and Engineering. The sample preparation for TbInO3 was supported by DOE DEFG02-07ER46382. The sample preparation for YbRu2Ge2 was supported by Gordon and Betty Moore Foundation GBMF9068.
Publisher Copyright:
© Published under licence by IOP Publishing Ltd.
PY - 2022/3/17
Y1 - 2022/3/17
N2 - We present Raman-scattering results for three materials, CeB6, TbInO3, and YbRu2Ge2, to illustrate the essential aspects of crystal-field (CF) excitations and quadrupolar fluctuations of 4f-electron systems. For CF excitations, we illustrate how the 4f orbits are split by spin-orbit coupling and CF potential by presenting spectra for inter- and intra-multiplet excitations over a large energy range. We discuss identification of the CF ground state and establishment of low-energy CF level scheme from the symmetry and energy of measured CF excitations. In addition, we demonstrate that the CF linewidth is a sensitive probe of electron correlation by virtue of self-energy effect. For quadrupolar fluctuations, we discuss both ferroquadrupolar (FQ) and antiferroquadrupolar (AFQ) cases. Long-wavelength quadrupolar fluctuations of the same symmetry as the FQ order parameter persists well above the transition temperature, from which the strength of electronic intersite quadrupolar interaction can be evaluated. The tendency towards AFQ ordering induces ferromagnetic correlation between neighboring 4f-ion sites, leading to long-wavelength magnetic fluctuations.
AB - We present Raman-scattering results for three materials, CeB6, TbInO3, and YbRu2Ge2, to illustrate the essential aspects of crystal-field (CF) excitations and quadrupolar fluctuations of 4f-electron systems. For CF excitations, we illustrate how the 4f orbits are split by spin-orbit coupling and CF potential by presenting spectra for inter- and intra-multiplet excitations over a large energy range. We discuss identification of the CF ground state and establishment of low-energy CF level scheme from the symmetry and energy of measured CF excitations. In addition, we demonstrate that the CF linewidth is a sensitive probe of electron correlation by virtue of self-energy effect. For quadrupolar fluctuations, we discuss both ferroquadrupolar (FQ) and antiferroquadrupolar (AFQ) cases. Long-wavelength quadrupolar fluctuations of the same symmetry as the FQ order parameter persists well above the transition temperature, from which the strength of electronic intersite quadrupolar interaction can be evaluated. The tendency towards AFQ ordering induces ferromagnetic correlation between neighboring 4f-ion sites, leading to long-wavelength magnetic fluctuations.
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U2 - 10.1088/1742-6596/2164/1/012054
DO - 10.1088/1742-6596/2164/1/012054
M3 - Conference article
AN - SCOPUS:85127221042
SN - 1742-6588
VL - 2164
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
IS - 1
M1 - 012054
T2 - 2020 International Conference on Strongly Correlated Electron Systems, SCES 2020
Y2 - 27 September 2021 through 1 October 2021
ER -