Shen S C, Chen B B, Xue H X, Cao G, Li C J, Wang X X, Hong Y P, Guo G P, Dou R F, Xiong C M, He L, Nie J C
Department of Physics, Beijing Normal University, Beijing 100875, China.
Key Laboratory of Quantum Information, CAS, University of Science and Technology of China, Hefei, Anhui 230026, China.
Sci Rep. 2016 Jul 5;6:28379. doi: 10.1038/srep28379.
The fundamental parameters of the superconducting state such as coherence length and pairing strength are essential for understanding the nature of superconductivity. These parameters can be estimated by measuring critical parameters such as upper critical field, Hc2. In this work, Hc2 of a superconducting (110) LaAlO3/SrTiO3 interface is determined through magnetoresistive measurements as a function of the gate voltage, VG. When VG increases, the critical temperature has a dome-like shape, while Hc2 monotonically decreases. This relationship of independence between the variation of Tc and of Hc2 suggests that the Cooper pairing potential is stronger in the underdoped region and the coherence length increases with the increase of VG. The result is as for high temperature superconducting cuprates and it is different than for conventional low temperature superconductors.
超导态的基本参数，如相干长度和配对强度，对于理解超导的本质至关重要。这些参数可以通过测量诸如上临界场Hc2等临界参数来估算。在这项工作中，通过磁阻测量确定了超导（110）LaAlO3/SrTiO3界面的Hc2作为栅极电压VG的函数。当VG增加时，临界温度呈穹顶状，而Hc2单调下降。Tc和Hc2变化之间的这种独立关系表明，在欠掺杂区域库珀对势更强，并且相干长度随着VG的增加而增加。该结果与高温超导铜酸盐的情况相同，与传统低温超导体的情况不同。
