TY - JOUR
T1 - Lattice dynamics of the heavy-fermion compound URu2Si2
AU - Buhot, J.
AU - Méasson, M. A.
AU - Gallais, Y.
AU - Cazayous, M.
AU - Sacuto, A.
AU - Bourdarot, F.
AU - Raymond, S.
AU - Lapertot, G.
AU - Aoki, D.
AU - Regnault, L. P.
AU - Ivanov, A.
AU - Piekarz, P.
AU - Parlinski, K.
AU - Legut, D.
AU - Homes, C. C.
AU - Lejay, P.
AU - Lobo, R. P.S.M.
N1 - Publisher Copyright:
© 2015 American Physical Society.
PY - 2015/1/26
Y1 - 2015/1/26
N2 - We report a comprehensive investigation of the lattice dynamics of URu2Si2 as a function of temperature using Raman scattering, optical conductivity, and inelastic neutron scattering measurements as well as theoretical ab initio calculations. The main effects on the optical phonon modes are related to Kondo physics. The B1g (Γ3 symmetry) phonon mode slightly softens below ∼100K, in connection with the previously reported softening of the elastic constant, C11-C12, of the same symmetry, both observations suggesting a B1g symmetry-breaking instability in the Kondo regime. Through optical conductivity, we detect clear signatures of strong electron-phonon coupling, with temperature-dependent spectral weight and Fano line shape of some phonon modes. Surprisingly, the line shapes of two phonon modes, Eu(1) and A2u(2), show opposite temperature dependencies. The A2u(2) mode loses its Fano shape below 150 K, whereas the Eu(1) mode acquires it below 100 K, in the Kondo crossover regime. This may point to momentum-dependent Kondo physics. By inelastic neutron-scattering measurements we have drawn the full dispersion of the phonon modes between 300 and 2 K. No remarkable temperature dependence has been obtained, including through the hidden order transition. Ab initio calculations with the spin-orbit coupling are in good agreement with the data except for a few low-energy branches with propagation in the (a,b) plane.
AB - We report a comprehensive investigation of the lattice dynamics of URu2Si2 as a function of temperature using Raman scattering, optical conductivity, and inelastic neutron scattering measurements as well as theoretical ab initio calculations. The main effects on the optical phonon modes are related to Kondo physics. The B1g (Γ3 symmetry) phonon mode slightly softens below ∼100K, in connection with the previously reported softening of the elastic constant, C11-C12, of the same symmetry, both observations suggesting a B1g symmetry-breaking instability in the Kondo regime. Through optical conductivity, we detect clear signatures of strong electron-phonon coupling, with temperature-dependent spectral weight and Fano line shape of some phonon modes. Surprisingly, the line shapes of two phonon modes, Eu(1) and A2u(2), show opposite temperature dependencies. The A2u(2) mode loses its Fano shape below 150 K, whereas the Eu(1) mode acquires it below 100 K, in the Kondo crossover regime. This may point to momentum-dependent Kondo physics. By inelastic neutron-scattering measurements we have drawn the full dispersion of the phonon modes between 300 and 2 K. No remarkable temperature dependence has been obtained, including through the hidden order transition. Ab initio calculations with the spin-orbit coupling are in good agreement with the data except for a few low-energy branches with propagation in the (a,b) plane.
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U2 - 10.1103/PhysRevB.91.035129
DO - 10.1103/PhysRevB.91.035129
M3 - Article
AN - SCOPUS:84921804574
VL - 91
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 0163-1829
IS - 3
M1 - 035129
ER -