Fluctuating charge-density waves in a cuprate superconductor.
Fluctuating charge-density waves in a cuprate superconductor.
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DOI：
10.1038/nmat3571
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发表时间：
2013-01
期刊：
影响因子：
41.2
通讯作者：
D. Torchinsky;F. Mahmood;A. Bollinger;I. Božović;N. Gedik
中科院分区：
文献类型：
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作者：
D. Torchinsky;F. Mahmood;A. Bollinger;I. Božović;N. Gedik
具有高温超导性（HTS）的铜材料也表现出各种形式的电荷和自旋有序，，，，，，其意义尚未完全了解。到目前为止，静态电荷密度波（CDWs）仅在特定掺杂水平下或在外加场中被衍射探针检测到。然而，动态cdw也可能更广泛地存在，它们的检测、表征及其与高温超导的关系仍是有待解决的问题。本文提出了一种基于超快光谱的方法来检测铜酸盐中CDW波动的存在并测量其寿命。在欠掺杂的la1.9 sr0.1 cuo4薄膜（Tc= 26 K）中，我们观察到CDW的集体激发持续到100 K。这种动态CDW波动的特征寿命为2ps atT= 5k，降至0.5 ps atT= 100k。相比之下，在最佳掺杂的la1.84 sr0.16 cuo4薄膜（Tc= 38.5 K）中，我们在任何温度下都没有检测到波动的cdw特征，这有利于竞争情景。这项工作为研究各种超导体和其他材料的波动有序参数开辟了一条道路。
Cuprate materials hosting high-temperature superconductivity (HTS) also exhibit various forms of charge and spin ordering,,,,,whose significance is not fully understood. So far, static charge-density waves (CDWs) have been detected by diffraction probes only at particular doping levels,,or in an applied external field . However, dynamic CDWs may also be present more broadly and their detection, characterization and relationship with HTS remain open problems. Here we present a method based on ultrafast spectroscopy to detect the presence and measure the lifetimes of CDW fluctuations in cuprates. In an underdoped La1.9Sr0.1CuO4film (Tc= 26 K), we observe collective excitations of CDW that persist up to 100 K. This dynamic CDW fluctuates with a characteristic lifetime of 2 ps atT= 5 K that decreases to 0.5 ps atT= 100 K. In contrast, in an optimally doped La1.84Sr0.16CuO4film (Tc= 38.5 K), we detect no signatures of fluctuating CDWs at any temperature, favouring the competition scenario. This work forges a path for studying fluctuating order parameters in various superconductors and other materials.