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arXiv 0707.2397cond-mat.supr-concond-mat.str-el
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强欠掺杂Cu_2O_3薄膜超流密度的量子临界行为

Quantum critical behaviour in the superfluid density of strongly underdoped ultrathin cuprate films

Iulian Hetel, Thomas R. Lemberger, Mohit Randeria

摘要:

高温超导体物理学中的一个中心问题是理解单个氧化铜层或双层(铜氧化物中的基本结构单元)内的超导性,以及它是如何随着掺杂不足而丧失的。随着可动空穴从CuO_2面被去除,晶体和厚膜中的转变温度T_C和超流密度n_S以令人惊讶的相关方式降低。我们试图阐明的内在物理双层在强烈欠掺杂制度,超导性消失的临界掺杂水平附近。本文报道了薄如两个氧化铜双层膜的Y_{1-x} Ca_xBa_2Cu_3 O_{7-δ}薄膜中n_S(T)的测量结果,T_C低至3 K。除了在T_C处观察到二维Kosterlitz-Erasless-Berezinski跃迁外,我们还观察到T_C随n_S(0)的显著标度,这表明欠掺杂时超导性的消失是由于T = 0的二维量子临界点附近的量子涨落。

英文摘要:

A central issue in the physics of high temperature superconductors is to understand superconductivity within a single copper-oxide layer or bilayer, the fundamental structural unit in the cuprates, and how it is lost with underdoping. As mobile holes are removed from the CuO_2 planes, the transition temperature T_C and superfluid density n_S decrease in a surprisingly correlated fashion in crystals and thick films. We seek to elucidate the intrinsic physics of bilayers in the strongly underdoped regime, near the critical doping level where superconductivity disappears. We report measurements of n_S(T) in films of Y_{1-x}Ca_xBa_2Cu_3O_{7-δ} as thin as two copper-oxide bilayers with T_C's as low as 3 K. In addition to seeing the two-dimensional (2D) Kosterlitz-Thouless-Berezinski transition at T_C, we observe a remarkable scaling of T_C with n_S(0) that demonstrates that the disappearance of superconductivity with underdoping is due to quantum fluctuations near a T = 0 2D quantum critical point.

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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