2004/11/16 by Y. Tanaka, Satoshi Kashiwaya, S. Kashiwaya +2 · 1 citation
Physics and Astronomy · #Advanced Condensed Matter Physics #Andreev reflection #Condensed matter physics #Layer (electronics) #Materials science #Metal #Nanotechnology #Physics #Physics of Superconductivity and Magnetism #Proximity effect (electron beam lithography) #Quantum and electron transport phenomena #Superconductivity #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.71.094513
arxiv created 2004/11/16 · openalex publication_date 2005/03/25 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Enhanced proximity effect by the midgap Andreev resonant state (MARS) in a diffusive normal-metal/insulator/triplet superconductor (DN/TS) junction is studied based on the Keldysh-Nambu quasiclassical Green's-function formalism. By choosing a p-wave superconductor as a typical example of the TS, conductance of the junction and the spatial variation of the quasiparticle local density of states (LDOS) in the DN are calculated as the function of the magnitudes of the resistance Rd, Thouless energy in the DN, and the transparency of the insulating barrier. The resulting conductance spectrum has a zero-bias conductance peak (ZBCP) and the LDOS has a zero energy peak (ZEP) except for \ensuremathα=\ensuremathπ∕2 (0\ensuremath\leqslant\ensuremathα\ensuremath\leqslant\ensuremathπ∕2), where \ensuremathα denotes the angle between the lobe direction of the p-wave pair potential and the normal to the interface. The widths of the ZBCP and the ZEP are reduced with the increase of Rd while their heights are drastically enhanced. These peaks are revealed to be suppressed by applying a magnetic field. When the magnitude of Rd∕R0 is sufficiently large, the total zero voltage resistance of the junction is almost independent of the Rd for \ensuremathα\ensuremath≠\ensuremathπ∕2. The extreme case is \ensuremathα=0, where total zero voltage resistance is always R0∕2. We also studied the charge transport in px+ipy-wave junctions, where only the quasiparticles with perpendicular injection feel the MARS. Even in this case, the resulting LDOS in the DN has a ZEP. Thus the existence of the ZEP in the LDOS of the DN region is a remarkable feature for DN/TS junctions which have never been expected for the DN/singlet superconductor junctions where the MARS and proximity effect compete with each other. Based on these results, a crucial test to identify triplet pairing superconductors based on tunneling experiments is proposed.