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arXiv 2201.07854cond-mat.supr-con
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平面Cu和O NMR及铜氧化物超导体的赝能隙

Planar Cu and O NMR and the Pseudogap of Cuprate Superconductors

Marija Avramovska, Jakob Nachtigal, Stefan Tsankov, Jürgen Haase

摘要:

最近,对铜氧化物高温超导体所有可用的平面氧位移和弛豫数据的分析表明,这些数据可以用来自所有铜氧化物共同的金属态密度的简单自旋磁化率来理解。它在费米面上带有一个与掺杂有关但与温度无关的赝能隙,这导致了与正常金属行为的偏离,在比热方面也是如此。在这里,一个更连贯的,公正的评估,所有的数据,包括平面铜,并讨论了后果,因为平面铜数据收集和分析之前的O数据。主要的发现是,平面Cu移位的一个方向的外部磁场很大程度上遵循相同的状态和赝隙。这解释了最近提出的移位抑制,这导致了与最初提出的反铁磁自旋波动引起的弛豫增强相反的Korringa关系的失败。然而,仍然需要第二个自旋分量,似乎是与铜$3d(x^2-y^2)$孔解释复杂的铜位移各向异性和家庭的依赖。此外,有人认为,最近报道的平面铜弛豫是相当普遍的铜酸盐,必须与这个普遍的态密度和第二自旋分量,而不是由简单的赝能隙的影响。因此,虽然在平面Cu数据中也发现了这种具有赝能隙的通用金属态密度,但仍然需要更详细的方案来避开平面O。

英文摘要:

Recently, an analysis of all available planar oxygen shift and relaxation data for the cuprate high-temperature superconductors showed that the data can be understood with a simple spin susceptibility from a metallic density of states common to all cuprates. It carries a doping dependent but temperature independent pseudogap at the Fermi surface, which causes the deviations from normal metallic behavior, also in the specific heat. Here, a more coherent, unbiased assessment of all data, including planar Cu, is presented and consequences are discussed, since the planar Cu data were collected and analyzed prior to the O data. The main finding is that the planar Cu shifts for one direction of the external magnetic field largely follow from the same states and pseudogap. This explains the shift suppression stated more recently, which leads to the failure of the Korringa relation in contrast to an enhancement of the relaxation due to antiferromagnetic spin fluctuations originally proposed. However, there is still the need for a second spin component that appears to be associated with the Cu $3d(x^2-y^2)$ hole to explain the complex Cu shift anisotropy and family dependence. Furthermore, it is argued that the planar Cu relaxation which was reported recently to be rather ubiquitous for the cuprates, must be related to this universal density of states and the second spin component, while not being affected by the simple pseudogap. Thus, while this universal metallic density of states with a pseudogap is also found in the planar Cu data, there is still need for a more elaborate scenario that eludes planar O.

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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