论文标题
为什么在高温超导体中从弱电子 - 音波耦合的交叉中发生最大TC？
Why does maximum Tc occur at the cross-over from weak to strong electron-phonon coupling in high temperature superconductors?
论文作者
论文摘要
在丘比特超导体中，在平面内Cu-O距离接近〜1.92埃的化合物中观察到了明显的超导TC。另一方面，电子音波耦合lambda的直接测量作为Cu-O距离的函数显示明显的线性相关性，这意味着TC是Lambda的强烈非线性函数。传统的超导性理论基于电子 - 光子相互作用预测TC对电子声子耦合常数的单调依赖性，这使得它们与观察到的行为不相容。观察到的交叉行为随Lambda的函数，表明TC发生在从弱耦合到强耦合的交叉上，这也与载体定位的发作有关。在两个组成的超导性场景中，与观察到的异常行为一致的局部和巡回载体的动态交换的共存，并被认为是理解实现高TC机制的关键。
In cuprate superconductors, a pronounced maximum of superconducting Tc is observed in compounds that have an in-plane Cu-O distance close to ~1.92 Angstroms. On the other hand, direct measurements of the electron-phonon coupling lambda as a function of Cu-O distance show a clear linear correlation, implying that Tc is a strongly non-linear function of lambda. Conventional superconductivity theories based on the electron-phonon interaction predict a monotonic dependence of Tc on electron phonon coupling constant, which makes them incompatible with the observed behaviour. The observed cross-over behaviour as a function of lambda suggests that Tc occurs at the cross-over from weak to strong coupling, which is also associated with the onset of carrier localization. A coexistence, with a dynamical exchange of localized and itinerant carriers in a two-component superconductivity scenario are in agreement with the observed anomalous behavior and are suggested to be the key to understanding the mechanism for achieving high Tc.
