Low-temperature vortex liquid in La 2− x Sr x CuO 4
Low-temperature vortex liquid in La 2− x Sr x CuO 4
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DOI：
10.1038/nphys563
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发表时间：
2007-02
期刊：
影响因子：
19.6
通讯作者：
Lu Li;J. Checkelsky;S. Komiya;Y. Ando;N. Ong
中科院分区：
文献类型：
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作者：
Lu Li;J. Checkelsky;S. Komiya;Y. Ando;N. Ong
在氧化铜超导体中，轻掺杂（小掺杂浓度，x）区域是主要的兴趣，因为超导性，反铁磁性和赝隙状态在临界掺杂值xc附近聚集在一起。但是在非常低的温度T下，超导性是如何被破坏的，目前还不清楚，，，，。在某个临界值xc时，对凝结物会突然消失吗？还是凝结水的相相干性被自发涡破坏了——就像在温度升高时的情况一样（参考文献，，）？到目前为止，在相位图的这一区域，低能级的磁化数据非常稀疏。本文报道了La2−xSrxCuO4的转矩磁强计测量结果，结果表明，在零磁场下，量子相位涨落破坏了超导性atxc≈0.055。相无序凝聚物在tox=0.03下存活。在有限场dh中，涡旋固-液转变发生在低于依赖场Hc2的位置。所得到的相图揭示了量子涡旋液体占据x - h平面的很大一部分。
In copper oxide superconductors, the lightly doped (small dopant concentration,x) region is of major interest,because superconductivity, antiferromagnetism and the pseudogap state come together near a critical doping value,xc. But the way in which superconductivity is destroyed asxis decreased at very low temperatures,T, is not clear,,,,. Does the pair condensate vanish abruptly at a critical value,xc? Or is phase coherence of the condensate destroyed by spontaneous vortices—as is the case at elevatedT(refs , , )? So far, magnetization data at lowTare very sparse in this region of the phase diagram. Here, we report torque magnetometry measurements on La2−xSrxCuO4, which show that, in zero magnetic field, quantum phase fluctuations destroy superconductivity atxc≈0.055. The phase-disordered condensate survives tox=0.03. In finite fieldH, the vortex solid-to-liquid transition occurs atHlower than the depairing field,Hc2. The resulting phase diagram reveals the large fraction of thex–Hplane occupied by the quantum vortex liquid.