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arXiv 0705.3836cond-mat.str-elcond-mat.supr-con
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铜氧化物超导体中库珀对的出现、d波对偶性和phase diagram

Emergence of Cooper pairs, d-wave duality and the phase diagram of cuprate superconductors

Zlatko Tesanovic

摘要:

BCS理论描述了库珀对的形成和它们瞬间“玻色凝聚”成超导态。氦原子是预先形成的玻色子,除了它们的凝聚超流态之外,还可以形成量子固体,缺乏相位相干性。在这里,我们表明,库珀对的命运可以比BCS或氦的范例更多样化。在铜氧化物d波超导体(dSC)中,库珀对本质上是非局域物体,具有质心和相对运动。随着掺杂的减少,质心波动迫使相关的dSC进入具有增强的抗磁性和鲁棒但短程的超导有序的状态。在极端的掺杂不足,相对波动接管和两个赝隙-"小“(电荷)和”大“(自旋)-自然出现从理论中,作为库珀对”衰变“和电荷”从自旋单线态键。随后的基态由对角(主要是反铁磁)关联而不是超导(非对角)关联控制。该理论被用来解释最近的几个实验,并得出有关相图的一般结论。

英文摘要:

BCS theory describes the formation of Cooper pairs and their instant "Bose condensation" into a superconducting state. Helium atoms are preformed bosons and, in addition to their condensed superfluid state, can also form a quantum solid, lacking phase-coherence. Here we show that the fate of Cooper pairs can be more varied than the BCS or helium paradigms. In copper-oxide d-wave superconductors (dSC) Cooper pairs are intrinsically non-local objects, with both center-of-mass and relative motions. As doping decreases, the center-of mass fluctuations force a correlated dSC into a state with enhanced diamagnetism and robust but short-ranged superconducting order. At extreme underdoping, the relative fluctuations take over and two pseudogaps -- ``small'' (charge) and ``large'' (spin) -- emerge naturally from the theory, as Cooper pairs ``disintegrate'' and charge ``detaches'' from spin-singlet bonds. The ensuing ground state(s) are governed by diagonal (mostly antiferromagnetic) rather than by superconducting (off-diagonal) correlations. The theory is used to account for several recent experiments and to draw general conclusions about the phase diagram.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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