Correlation between scale-invariant normal-state resistivity and superconductivity in an electron-doped cuprate
Correlation between scale-invariant normal-state resistivity and superconductivity in an electron-doped cuprate
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DOI：
10.1126/sciadv.aav6753
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发表时间：
2019-05-01
期刊：
影响因子：
13.6
通讯作者：
Greene, Richard L.
中科院分区：
文献类型：
--
作者：
Sarkar, Tarapada;Mandal, P. R.;Greene, Richard L.
高温超导铜氧化物的正常态的理解是至关重要的最终理解的长期存在的问题的超导性本身的起源。这种所谓的“奇怪金属”状态被认为与隐藏在超导性之下的量子临界点（QCP）有关。在电子掺杂的铜氧化物中，与空穴掺杂的铜氧化物相反，可以在非常低的温度和低磁场下进入正常状态，以研究这种假定的QCP并探测这些材料的T -> K状态。我们报告的低温正常状态下的磁电阻（MR）的n型铜酸盐系统La 2-xCexCuO 4的测量和发现，它的特点是由一个线性的场行为，它遵循的比例关系与施加的磁场和温度，掺杂（x）以上的推定QCP（x = 0.14）。非常规线性磁电阻的大小随T_c的减小而减小，并在超导圆顶的端部（x = 0.175）趋于零，在此之上发现常规的二次磁电阻，这些结果表明奇异金属态的量子临界激发与高T_c超导性之间有很强的相关性。
An understanding of the normal state in the high-temperature superconducting cuprates is crucial to the ultimate understanding of the long-standing problem of the origin of the superconductivity itself. This so-called "strange metal" state is thought to be associated with a quantum critical point (QCP) hidden beneath the superconductivity. In electron-doped cuprates-in contrast to hole-doped cuprates-it is possible to access the normal state at very low temperatures and low magnetic fields to study this putative QCP and to probe the T -> K state of these materials. We report measurements of the low-temperature normal-state magnetoresistance (MR) of the n-type cuprate system La2-xCexCuO4 and find that it is characterized by a linear-in-field behavior, which follows a scaling relation with applied field and temperature, for doping (x) above the putative QCP (x = 0.14). The magnitude of the unconventional linear MR decreases as T-c decreases and goes to zero at the end of the superconducting dome (x similar to 0.175) above which a conventional quadratic MR is found. These results show that there is a strong correlation between the quantum critical excitations of the strange metal state and the high-T-c superconductivity.