Nanometer scale mapping of the density of states in an inhomogeneous superconductor
Nanometer scale mapping of the density of states in an inhomogeneous superconductor
复制标题
非均匀超导体中状态密度的纳米尺度映射
DOI：
10.1209/epl/i2001-00232-4
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发表时间：
2000
期刊：
影响因子：
1.8
通讯作者：
J. Klein
中科院分区：
文献类型：
--
作者：
T. Cren;D. Roditchev;W. Sacks;J. Klein
利用高速扫描隧道谱（STS），我们对Bi₂₋ₓPbₓSr₂CaCu₂O₈₊₆单晶中的准粒子态密度（DOS）进行了全面测绘。在5 K下进行的测量显示出纳米尺度上局部态密度重要变化的复杂空间模式。以明显的超导能隙为特征的超导区域与我们归因于赝能隙的无峰能隙结构区域共存。在大的超导区域内，光谱显示出强烈的峰/谷/驼峰特征，与原始的Bi₂Sr₂CaCu₂O₈₊₆情况相同。相反，在非常小的超导区域中，这种精细结构减弱。局部态密度的这种行为表明，峰/谷/驼峰精细结构不仅是超导态的结果，而且还与相位相干的尺度直接相关。讨论了Bi - Pb替代无序的作用。
Using high-speed scanning tunneling spectroscopy (STS), we perform a full mapping of the quasiparticle density of states (DOS) in single crystals of Bi2 − xPbxSr2CaCu208 + δ. The measurements carried out at 5 K showed a complex spatial pattern of important variations of the local DOS on the nanometer scale. Superconducting areas, characterized by a well-pronounced superconducting gap, are coexisting with regions of a peakless gap structure which we attribute to the pseudogap. Within the large superconducting regions, the spectra reveal strong peak/dip/hump signatures, identical to the pristine Bi2Sr2CaCu208 + δ case. On the contrary, in very small superconducting regions this fine structure is attenuated. Such a behavior of the local DOS suggests that the peak/dip/hump fine structure is not only a consequence of the superconducting state, but is also directly related to the scale of the phase coherence. The role of Bi-Pb substitutional disorder is discussed.