Zero-bias anomaly in p-wave superconductor

Abstract

It was shown some time ago that a magnetic field penetrates a triplet non-chiral superconductor described by the (three-dimensional) vector order parameter as an array of magnetic skyrmions, a texture carrying two units of magnetic flux. Magnetic skyrmions do not have a normal core in contrast to Abrikosov vortices. The spectrum of Andreev midgap states of this coreless topological defect in p-wave isotropic superconductors with single parabolic band is calculated. It is shown that a magnetic field can be used to tune the Andreev state energy precisely to zero (these states are not topologically protected). They can be further stabilized and manipulated by pinning of the skyrmions on columnar defects or nanoholes. In contrast to Majorana modes in chiral p-wave superconductor, the tunneling between ZES within neighboring skyrmions is prohibited due to their high angular momentum. Experimental signatures of these states are discussed.