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arXiv 0909.3112cond-mat.supr-con
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Josephson扫描隧道显微镜:超导序参量的局域直接探测

Josephson scanning tunneling microscopy: A local and direct probe of the superconducting order parameter

Hikari Kimura, R. P. Barber, S. Ono, Yoichi Ando, R. C. Dynes

摘要:

本文报道了真空劈裂Bi_2Sr_2CaCu_2O_8(BSCCO)样品表面超导超流的直接测量结果。这些测量是通过使用配备有超导尖端的扫描隧道显微镜(STM)通过约瑟夫森隧道进入样品来完成的。横向距离小于超导相干长度的STM的空间分辨率允许它揭示BSCCO的对波函数中的局部不均匀性。仪器的性能首先表现出与约瑟夫森测量的铅膜,然后由层状超导体NbSe 2。相关的测量参数,约瑟夫森ICRN产品,BCS超导体和高转变温度超导体的范围内进行了讨论。ICRN产品和准粒子态密度(DOS)间隙的本地关系的范围内的相图BSCCO。这些测量可以产生过大的电流密度,并且已经发现会改变BSCCO中的局部DOS。对这种效应进行了系统的研究,以确定这些实验的实际测量限值。还讨论了制备BSCCO表面的替代方法。

英文摘要:

Direct measurements of the superconducting superfluid on the surface of vacuum-cleaved Bi2Sr2CaCu2O8(BSCCO) samples are reported. These measurements are accomplished via Josephson tunneling into the sample using a scanning tunneling microscope (STM) equipped with a superconducting tip. The spatial resolution of the STM of lateral distances less than the superconducting coherence length allows it to reveal local inhomogeneities in the pair wavefunction of the BSCCO. Instrument performance is demonstrated first with Josephson measurements of Pb films followed by the layered superconductor NbSe2. The relevant measurement parameter, the Josephson ICRN product, is discussed within the context of both BCS superconductors and the high transition temperature superconductors. The local relationship between the ICRN product and the quasiparticle density of states (DOS) gap are presented within the context of phase diagrams for BSCCO. Excessive current densities can be produced with these measurements and have been found to alter the local DOS in the BSCCO. Systematic studies of this effect were performed to determine the practical measurement limits for these experiments. Alternative methods for preparation of the BSCCO surface are also discussed.

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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