Conspiring interactions in a cuprate More than 30 years after the discovery of high-temperature superconductivity in copper oxides, its mechanism remains a mystery. Electron pairing mediated solely by lattice vibrations—phonons—is thought to be insufficient to account for the high transition temperatures. He et al. found a rapid and correlated increase of the superconducting gap and electron-phonon interactions as the chemical composition of their bismuth-based cuprate samples was varied across a critical doping concentration. The interplay of electron-phonon with electron-electron interactions may lead to enhanced transition temperatures. Science, this issue p. 62 Angle-resolved photoemission uncovers an interplay between various types of interaction in a cuprate superconductor. Electron-boson coupling plays a key role in superconductivity for many systems. However, in copper-based high–critical temperature (Tc) superconductors, its relation to superconductivity remains controversial despite strong spectroscopic fingerprints. In this study, we used angle-resolved photoemission spectroscopy to find a pronounced correlation between the superconducting gap and the bosonic coupling strength near the Brillouin zone boundary in Bi2Sr2CaCu2O8+δ. The bosonic coupling strength rapidly increases from the overdoped Fermi liquid regime to the optimally doped strange metal, concomitant with the quadrupled superconducting gap and the doubled gap-to-Tc ratio across the pseudogap boundary. This synchronized lattice and electronic response suggests that the effects of electronic interaction and the electron-phonon coupling (EPC) reinforce each other in a positive-feedback loop upon entering the strange-metal regime, which in turn drives a stronger superconductivity.

中文翻译：

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通过 Bi-2212 中的临界掺杂快速改变超导性和电子-声子耦合

铜酸盐中的相互作用 在发现氧化铜的高温超导性 30 多年后，其机制仍然是个谜。仅由晶格振动（声子）介导的电子配对被认为不足以解释高转变温度。他等人。发现超导间隙和电子 - 声子相互作用快速且相关地增加，因为他们的基于铋的铜酸盐样品的化学成分在临界掺杂浓度范围内变化。电子-声子与电子-电子相互作用的相互作用可能导致转变温度升高。科学，这个问题 p。62 角分辨光电发射揭示了铜酸盐超导体中各种相互作用之间的相互作用。电子-玻色子耦合在许多系统的超导性中起着关键作用。然而，在铜基高临界温度 (Tc) 超导体中，尽管具有很强的光谱指纹，但其与超导性的关系仍然存在争议。在这项研究中，我们使用角分辨光电子能谱来发现超导间隙与 Bi2Sr2CaCu2O8+δ 中布里渊区边界附近的玻色子耦合强度之间的显着相关性。玻色子耦合强度从过度掺杂的费米液体状态迅速增加到最佳掺杂的奇异金属，伴随着四倍的超导间隙和跨越赝隙边界的两倍的间隙与 Tc 比。