第9期 王亚愚：Electronic structure and electronic order in Bi₂Sr₂Ca₂Cu₃O_10+δ trilayer cuprates

2020年8月26日（周三）15:00-16:00
报告人：王亚愚  清华大学

摘要：A well-established trend in cuprate high temperature superconductors is that for each homologous series the maximum T_c increases with the number of CuO₂ planes per unit cell up to the trilayer limit. Trilayer cuprates not only have the highest T_c, but also have the unique situation with two types of inequivalent CuO₂ planes. In this talk, we present STM studies of the atomic scale electronic structure of Bi₂Sr₂Ca₂Cu₃O_10+δ (Bi-2223) trilayer cuprates with varied dopings. We find that most tunneling spectra exhibit two superconducting gaps, presumably from the inner and outer CuO₂ planes respectively. The superconducting properties show spatial variations that are correlated with the structural supermodulation, and the effect is much more pronounced in the underdoped regime. The two superconducting gaps both decrease rapidly with increasing doping, despite the nearly constant T_c in the overdoped regime. There is an absence of quasiparticle interference in the antinodal region of strongly overdoped Bi-2223, but instead an electronic order with   periodicity starts to emerge. More remarkably, this order also breaks the particle-hole symmetry, resulting in two asymmetric SC coherence peaks that alternate periodically in space. We propose that the key underlying physics for these anomalous observations is the intricate interaction between the two types of CuO₂ planes in Bi-2223, which leads to unique band dispersion of the Bogoliubov quasiparticles, especially in the antinodal regime.

报告人简介：Yayu Wang received his B.S. degree in physics from the University of Science and Technology of China in 1998 and his Ph.D. from Princeton University in 2004. From 2004 and 2007 he was a Miller research fellow at UC Berkeley. After a brief visit to MIT, he joined the physics department of Tsinghua University in December 2007. His recent research interests include transport studies of topological insulators and STM studies of high temperature superconductors.

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会议ID: 117 838 958（300人）

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