TY - JOUR
T1 - Effects of rattling phonons on the dynamics of quasiparticle excitation in the β-pyrochlore KOs2O6 Superconductor
AU - Shimono, Y.
AU - Shibauchi, T.
AU - Kasahara, Y.
AU - Kato, T.
AU - Hashimoto, K.
AU - Matsuda, Y.
AU - Yamaura, J.
AU - Nagao, Y.
AU - Hiroi, Z.
PY - 2007/6/22
Y1 - 2007/6/22
N2 - Microwave penetration depth λ and surface resistance at 27 GHz are measured in high quality crystals of KOs2O6. Firm evidence for fully gapped superconductivity is provided from λ(T). Below the second transition at Tp∼8K, the superfluid density shows a steplike change with a suppression of effective critical temperature Tc. Concurrently, the extracted quasiparticle scattering time shows a steep enhancement, indicating a strong coupling between the anomalous rattling motion of K ions and quasiparticles. The results imply that the rattling phonons help to enhance superconductivity, and that K sites freeze to an ordered state with long quasiparticle mean free path below Tp.
AB - Microwave penetration depth λ and surface resistance at 27 GHz are measured in high quality crystals of KOs2O6. Firm evidence for fully gapped superconductivity is provided from λ(T). Below the second transition at Tp∼8K, the superfluid density shows a steplike change with a suppression of effective critical temperature Tc. Concurrently, the extracted quasiparticle scattering time shows a steep enhancement, indicating a strong coupling between the anomalous rattling motion of K ions and quasiparticles. The results imply that the rattling phonons help to enhance superconductivity, and that K sites freeze to an ordered state with long quasiparticle mean free path below Tp.
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U2 - 10.1103/PhysRevLett.98.257004
DO - 10.1103/PhysRevLett.98.257004
M3 - Article
AN - SCOPUS:34547304155
SN - 0031-9007
VL - 98
JO - Physical Review Letters
JF - Physical Review Letters
IS - 25
M1 - 257004
ER -