Novel transport phenomena in spin-triplet superconductor

利用微加工技术，研究了自旋三重态p波超导体Sr_2RuO_4 （SRO）的局域输运特性。我们观察到一些新的现象，如(i)在几μm宽的弱结中电压-电流特性出现了非常规的滞后，（ii）超导临界电流密度大幅增强，截面减小到100 ^2以下。这些现象表明边缘态是在微加工SRO器件中形成的。我们还研究了微加工形成的SRO断结的隧道光谱。隧道光谱显示出宽的零偏电导峰，支持SRO中的手性纵波态。

Using micro fabrication techniques, we investigated local transport characteristics of spin-triplet p-wave superconductor Sr_2RuO_4 (SRO). We observed novel phenomena such as, (i) an unconventional hysteresis in voltage-current characteristics in a few μm-width weak junction, and (ii) a large enhancement of superconducting critical current density with reducing cross section below 100m^2. These phenomena imply that edge states are formed in a microfabricated SRO device. We also studied tunnel spectra of an SRO break junction formed by microfabrication. The tunnel spectra showed broad zero-bias conductance peaks, which supports the chiral p-wave state in SRO.