Details

Autor(en) / Beteiligte

• Alekseev, P A
• Mignot, J-M
• Nemkovski, K S
• Rybina, A V
• Lazukov, V N
• Ivanov, A S
• Iga, F
• Takabatake, T

Titel

Interplay of low-energy phonons and magnetic excitations in the Kondo insulator Y bB12

Ist Teil von

• Journal of physics. Condensed matter, 2012-04, Vol.24 (20)

Ort / Verlag

IOP Publishing

Erscheinungsjahr

2012

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Peculiarities in the lattice dynamics of the Kondo insulator Y bB12 have been studied by inelastic neutron scattering. Selected phonon modes were traced above and below the temperature region (T ∼ 50 K) where the gap opens in the electron density of states. The intensities of some low-energy modes exhibit an anomalous temperature dependence for q vectors close to the Brillouin zone boundary, suggesting a renormalization of the phonon eigenvectors. This effect is thought to arise from a coupling with magnetic excitations of the same symmetry, which exist at nearby energies. It is argued that this magnetovibrational coupling may in turn play a role in the steep temperature crossover existing in Y bB12 between the low-temperature (Kondo insulator) and high-temperature (incoherent spin-fluctuation) regimes, which is rapidly suppressed by lighter Zr substitution.