Impurity scattering in the Kitaev chain and its effect on odd-frequency spin-triplet pairing.

The Kitaev chain is the simplest model of topological superconductors hosting Majorana fermions that appear as zero-energy states at the edges. Its presence is linked to the emergence of odd-frequency pairing. We investigate the effect of an impurity in the Kitaev chain and study its impact on the odd-frequency spin-triplet pairing. We use a scattering approach to obtain the Green’s function of the semi-infinite Kitaev chain with a delta-function-type impurity potential within the quasi-classical regime analytically [1] and analyze the spatial dependence of the zero-energy LDOS and low-frequency odd-frequency component.

[1] Sparsh Mishra, Shun Tamura, Akito Kobayashi and Yukio Tanaka,
“Impact of impurity scattering on odd-frequency spin-triplet pairing near the edge of the Kitaev chain”, Phys. Rev. B 103, 024501