Quadrupolar effect and rattling motion in the heavy-fermion superconductor PrOs 4 Sb 12
Quadrupolar effect and rattling motion in the heavy-fermion superconductor PrOs 4 Sb 12
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DOI：
10.1103/physrevb.69.180511
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发表时间：
2004-04
影响因子：
3.7
通讯作者：
T. Goto;Y. Nemoto;Kazuhiro Sakai;Takashi Yamaguchi;M. Akatsu;T. Yanagisawa;H. Hazama;Kei Onuki-Kei-Onuk
中科院分区：
文献类型：
--
作者：
T. Goto;Y. Nemoto;Kazuhiro Sakai;Takashi Yamaguchi;M. Akatsu;T. Yanagisawa;H. Hazama;Kei Onuki-Kei-Onuk
研究了具有重费米子超导电性的填充Skutterudite{MATHROM{PROS}{4}{MATHROM{Sb}}{12}$的弹性性质。随着温度的降低，{(C}_{11}\保证数学{-}{C}_{12})/2$和${C}_{44}$的弹性软化表明，CEF态引起的四极涨落对超导相的库珀配对起作用。在30K左右的弹性常数中，德拜型弥散揭示了热激活的${{12}。由于Pr原子的偏心运动服从$\ensuremath{\tau}={\ensuremath{\tau}}_{0}\mathrm{exp}{(E/k}_{\mathrm{B}}T)$、尝试时间${\ensuremath{\tau}}_{0}=8.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}\mathrm{s}$和激活能而引起的_{23}$$E=168\mathm{K}。$值得注意的是，偏心运动的电荷涨落具有对称性，可能与四极涨落混合，增强${(C}_{11}\保证数学{-}{C}_{12})/2$略高于${T}_{\mathm{C}}的弹性软化。$
The elastic properties of a filled skutterudite ${\mathrm{PrOs}}_{4}{\mathrm{Sb}}_{12}$ with a heavy fermion superconductivity at ${T}_{\mathrm{C}}=1.85\mathrm{K}$ have been investigated. The elastic softening of ${(C}_{11}\ensuremath{-}{C}_{12})/2$ and ${C}_{44}$ with lowering temperature down to ${T}_{\mathrm{C}}$ indicates that the quadrupolar fluctuation due to the CEF state plays a role for the Cooper paring in superconducting phase of ${\mathrm{PrOs}}_{4}{\mathrm{Sb}}_{12}.$ A Debye-type dispersion in the elastic constants around 30 K revealed a thermally activated ${\ensuremath{\Gamma}}_{23}$ rattling due to the off-center Pr-atom motion obeying $\ensuremath{\tau}={\ensuremath{\tau}}_{0}\mathrm{exp}{(E/k}_{\mathrm{B}}T)$ with an attempt time ${\ensuremath{\tau}}_{0}=8.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}11}\mathrm{s}$ and an activation energy $E=168\mathrm{K}.$ It is remarkable that the charge fluctuation of the off-center motion with ${\ensuremath{\Gamma}}_{23}$ symmetry may mix with the quadrupolar fluctuation and enhance the elastic softening of ${(C}_{11}\ensuremath{-}{C}_{12})/2$ just above ${T}_{\mathrm{C}}.$