Spin-sensitive interference due to Majorana state on the interface between normal and superconducting leads

Abstract

We investigate the subgap spectrum and transport properties of the quantum dot on interface between the metallic and superconducting leads and additionally side-coupled to the edge of topological superconducting (TS) chain, hosting the Majorana quasiparticle. Due to chiral nature of the Majorana states only one spin component of the quantum dot electrons (say ↑) is directly affected, however the proximity induced on-dot pairing transmits its influence on the opposite spin as well. We investigate the unique interferometric patterns driven by the Majorana quasiparticle that are different for each spin component. We also address the spin-sensitive interplay with the Kondo effect manifested at the same zero-energy and we come to conclusion that quantum interferometry can unambiguously identify the Majorana quasiparticle.

Leakage of Majorana mode into correlated quantum dot nearby its singlet-doublet crossover

“…This comes from destructive feedback effect when the original QD level coincides with Majorana mode. Such destructive interference pattern has been described by our group [7,16]. We have pointed out that even when spectral weight of the zero-energy mode in spectrum of directly coupled spins is suppressed, the zero-energy mode in opposite spin channel would be enhanced.…”

Majorana oscillations modulated by Fano interference and degree of nonlocality in a topological superconducting-nanowire–quantum-dot system

“…Moreover, differential conductance as function of bias-voltage reveals fractional Fano-like resonances around eV = 0 with intriguing minimal and maximal values equal to e 2 /4h and 3e 2 /4h 31,38 . Similar fractional Fano interference process was already reported by Barański et al 32 in a T-shaped geometry with a QD between metallic and superconducting leads, side-coupled to a MBS. In such a system, the fractional interferometric behavior is related to the presence of MBS in the system, which scatters the electron waves, changing their phase 32 .…”

The Spin‐Dependent Coupling in the Hybrid Quantum Dot–Majorana Wire System

“…The competition (coexistence) between Majorana bound states and the Kondo effect can be examined using the quantum dot‐Majorana nanowire system. This system was analyzed experimentally and theoretically for different configurations of a quantum dot, Majorana nanowire, and the external leads. In our work, we examine the competition between Majorana bound states and the Kondo effect using the tunneling setup, in which the quantum dot is placed between two metallic leads (N‐QD‐N) and additionally it is side‐coupled to the Majorana nanowire (see Figure ) .…”

“…In our analysis we will focus on the influence of the Majorana bound states on the transport properties of the N‐QD‐N system, so we will assume that the s‐wave superconductor substrate does not interact with QD. The influence of the QD coupling with the SC substrate was analyzed previously . The connection of quantum dot with metallic lead leads to the Kondo effect, which produces the Kondo resonance pinned to the Fermi level of the metallic leads.…”