Unveiling the Superconducting Mechanism of Ba0.51K0.49BiO3
Unveiling the Superconducting Mechanism of Ba0.51K0.49BiO3
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揭示Ba0.51K0.49BiO3的超导机理
DOI：
10.1103/physrevlett.121.117002
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发表时间：
2018
影响因子：
8.6
通讯作者：
Feng D. L.
中科院分区：
文献类型：
--
作者：
Wen C. H. P.;Xu H. C.;Yao Q.;Peng R.;Niu X. H.;Chen Q. Y.;Liu Z. T.;Shen D. W.;Song Q.;Lou X.;Fang Y. F.;Liu X. S.;Song Y. H.;Jiao Y. J.;Duan T. F.;Wen H. H.;Dudin P.;Kotliar G.;Yin Z. P.;Feng D. L.
铋酸盐的高超导转变温度（）的机制尽管经过了30多年的广泛研究，但仍存在争议。我们的角分辨光电子能谱研究揭示了一个意想不到的34%以上的带宽比传统的密度泛函理论计算。这可以通过充分考虑长程库仑相互作用的计算来再现，这是由于Fock交换项导致的带宽扩展的第一个直接证明，Fock交换项是许多体物理学中长期接受但尚未证实的基本效应。此外，我们观察到各向同性的超导带隙，以及具有耦合常数的强电子-声子相互作用。这些发现解决了一个长期存在的谜团-是一个非凡的Bardeen-Cooper-Schrieffer超导体，其中长程库仑相互作用扩展了带宽，增强了电子-声子耦合，并产生了高。这种效应对于寻找新的超导体也至关重要。
The mechanism of high superconducting transition temperatures () in bismuthates remains under debate despite more than 30 years of extensive research. Our angle-resolved photoemission spectroscopy studies onreveal an unexpectedly 34% larger bandwidth than in conventional density functional theory calculations. This can be reproduced by calculations that fully account for long-range Coulomb interactions—the first direct demonstration of bandwidth expansion due to the Fock exchange term, a long-accepted and yet uncorroborated fundamental effect in many body physics.Furthermore, we observe an isotropic superconducting gap with, and strong electron-phonon interactions with a coupling constant. These findings solve a long-standing mystery—is an extraordinary Bardeen-Cooper-Schrieffer superconductor, where long-range Coulomb interactions expand the bandwidth, enhance electron-phonon coupling, and generate the high. Such effects will also be critical for finding new superconductors.