Kokales JD, Fournier P, Mercaldo LV, Talanov VV, Greene RL, Anlage SM
Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742-4111, USA.
Phys Rev Lett. 2000 Oct 23;85(17):3696-9. doi: 10.1103/PhysRevLett.85.3696.
We report microwave cavity perturbation measurements of the temperature dependence of the penetration depth, lambda(T), and conductivity, sigma(T) of Pr(2-x)Ce(x)CuO(4-delta) (PCCO) crystals, as well as parallel-plate resonator measurements of lambda(T) in PCCO thin films. Penetration depth measurements are also presented for a Nd(2-x)Ce(x)CuO(4-delta) (NCCO) crystal. We find that Deltalambda(T) has a power-law behavior for T<T(c)/3, and conclude that the electron-doped cuprate superconductors have nodes in the superconducting gap. Furthermore, using the surface impedance, we have derived the real part of the conductivity, sigma(1)(T), below T(c) and found a behavior similar to that observed in hole-doped cuprates.
我们报告了对Pr(2-x)Ce(x)CuO(4-δ)（PCCO）晶体的穿透深度λ(T)和电导率σ(T)随温度变化的微波腔微扰测量结果，以及对PCCO薄膜中λ(T)的平行板谐振器测量结果。还给出了Nd(2-x)Ce(x)CuO(4-δ)（NCCO）晶体的穿透深度测量结果。我们发现，对于T<Tc/3，Δλ(T)具有幂律行为，并得出电子掺杂铜酸盐超导体在超导能隙中有节点的结论。此外，利用表面阻抗，我们推导出了低于Tc时电导率的实部σ1(T)，并发现其行为与空穴掺杂铜酸盐中观察到的行为相似。
