arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0902.4314cond-mat.supr-con
收藏

双层铜氧化物超导体c轴红外响应的微观规范不变理论及超导诱导吸收带的起源

Microscopic gauge-invariant theory of the c-axis infrared response of bilayer cuprate superconductors and the origin of the superconductivity induced absorption bands

J. Chaloupka, C. Bernhard, D. Munzar

摘要:

我们报告的结果,我们的理论研究的c-轴的双层高Tc铜酸盐超导体的红外电导率的微观模型,涉及双层分裂(键合和反键合)带。重点是规范不变性的理论,这是必不可少的物理理解这些化合物的电动力学。光学响应的描述涉及局部(双层内和双层间)电流密度和局部电导率。局部电导率是用微观理论得到的,其中两个带的准粒子耦合到自旋涨落。耦合导致超导电性,并在广义Eliashberg理论的水平上描述。还解决了较简单的情况下,准粒子耦合的可分离和nonretarded相互作用。理论的规范不变性是通过引入适当的顶点修正来实现的。由此产生的模型的响应进行了详细的研究和解释的两个超导诱导峰的c轴电导率的实部的实验数据提出。在400/cm附近的峰值归因于双层内区域的集体模式,这是Bogolyubov-Anderson模式的模拟,在超导体的纵向响应理论中起着至关重要的作用。对于小值的双层分裂,其性质是类似的现象学约瑟夫森超晶格模型的横向等离子体激元。1000/cm附近的峰被解释为与通过分隔双层的间隔层的电子耦合有关的对断裂特征。

英文摘要:

We report on results of our theoretical study of the c-axis infrared conductivity of bilayer high-Tc cuprate superconductors using a microscopic model involving the bilayer-split (bonding and antibonding) bands. An emphasis is on the gauge-invariance of the theory, which turns out to be essential for the physical understanding of the electrodynamics of these compounds. The description of the optical response involves local (intra-bilayer and inter-bilayer) current densities and local conductivities. The local conductivities are obtained using a microscopic theory, where the quasiparticles of the two bands are coupled to spin fluctuations. The coupling leads to superconductivity and is described at the level of generalized Eliashberg theory. Also addressed is the simpler case of quasiparticles coupled by a separable and nonretarded interaction. The gauge invariance of the theory is achieved by including a suitable class of vertex corrections. The resulting response of the model is studied in detail and an interpretation of two superconductivity-induced peaks in the experimental data of the real part of the c-axis conductivity is proposed. The peak around 400/cm is attributed to a collective mode of the intra-bilayer regions, that is an analogue of the Bogolyubov-Anderson mode playing a crucial role in the theory of the longitudinal response of superconductors. For small values of the bilayer splitting, its nature is similar to that of the transverse plasmon of the phenomenological Josephson superlattice model. The peak around 1000/cm is interpreted as a pair breaking-feature that is related to the electronic coupling through the spacing layers separating the bilayers.

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。

↑