论文标题
BCS超导体的异常同位素效应具有两个玻色子模式
Anomalous isotope effect in BCS superconductors with two boson modes
论文作者
论文摘要
如果同位素系数$α<0 $或$α> 1/2 $，超导过渡温度中的同位素效应是异常的。在这项工作中，我们表明，如果声子和非呼应模式共存，则在Bardeen-Cooper-Schrieffer框架中自然会出现这种异常行为。与$α\ le1/2 $的标准Eliashberg理论（仅具有声子）的情况不同，同位素系数现在可以在同时存在声子和其他非呼应模式的情况下进行任意值。特别是，最引人注目的是，如果非常规的超导率是通过较低的非频率非Phonon Boson模式介导的，则配对的声子可以产生大的同位素系数$α> 1/2 $。根据我们的研究，讨论了对几个超导体家庭的影响。
The isotope effect in the superconducting transition temperature is anomalous if the isotope coefficient $α<0$ or $α>1/2$. In this work, we show that such anomalous behaviors can naturally arise within the Bardeen-Cooper-Schrieffer framework if both phonon and non-phonon modes coexist. Different from the case of the standard Eliashberg theory (with only phonon) in which $α\le1/2$, the isotope coefficient can now take arbitrary values in the simultaneous presence of phonon and the other non-phonon mode. In particular, most strikingly, a pair-breaking phonon can give rise to large isotope coefficient $α>1/2$ if the unconventional superconductivity is mediated by the lower frequency non-phonon boson mode. Based on our studies, implications on several families of superconductors are discussed.
