Anomalous Isotope Effect in Rattling-Induced Superconductor
Anomalous Isotope Effect in Rattling-Induced Superconductor
复制标题
震感超导体中的反常同位素效应
DOI：
10.1143/jpsj.81.114711
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Kunihiro Oshiba and Takashi Hotta
中科院分区：
文献类型：
--
作者：
K. Akiba;A. Miyake;H. Yaguchi;A. Matsuo;K. Kindo;Y. Iye;and M. Tokunaga;Kunihiro Oshiba and Takashi Hotta
为了阐明β-烧绿石氧化物中的库珀对是由客体原子的非谐振荡介导的，即，我们提出了一个实验来检测异常同位素效应。在公式Tc <$M-η中，T为超导转变温度，M为振子质量，发现指数η随客体原子势的非谐性增加而增加。我们预言，在振动诱导超导体中，η将大于1/2，这与由简谐声子引起的弱耦合超导体的η=1/2和包含库仑相互作用的强耦合超导体的η<1/2形成鲜明对比。
To clarify that the Cooper pair in β-pyrochlore oxides is mediated by the anharmonic oscillation of a guest atom, i.e.,rattling, we propose an experiment to detect an anomalous isotope effect. In the formulaTc∝M-η, whereTcis the superconducting transition temperature andMdenotes the mass of the oscillator, it is found that the exponent η increases with the increase in anharmonicity of the potential for the guest atom. We predict that η becomes larger than 1/2 in rattling-induced superconductors, in sharp contrast to η=1/2 for weak-coupling superconductivity due to harmonic phonons and η<1/2 for strong-coupling superconductivity with the inclusion of the effect of Coulomb interaction.