Majorana fermion realization and relevant transport processes in a triple-quantum dot system

Abstract

Nonequilibrium electronic transports through a system hosting three quantum dots hybridized with superconductors are investigated. By tuning the relative positions of the dot levels, we illustrate the existence of Majorana fermions and show that the Majorana feimions will either survive separately on single dots or distribute themselves among different dots with tunable probabilities. As a result, different physical mechanisms appear, including local Andreev reflection (LAR), cross Andreev reflection (CAR), and cross resonant tunneling (CRT). The resulting characteristics may be used to reveal the unique properties of Majorana fermions. In addition, we discuss the spin-polarized transports and find a pure spin current and a spin filter effect due to the joint effect of CRT and CAR, which is important for designing spintronic devices.

Floquet Majorana fermions in superconducting quantum dots

“…and β = µ 2 µ 3 4t 12 t 23 . In the case where µ 2 or µ 3 are zero the MFs are spatially separated [25]. Interestingly, the manipulation of the onsite-energies allows to change the localization of the MFs, which would be relevant for their detection in transport [10].…”

“…The existence of these exotic dynamical quasiparticles can be detected by connecting two metallic leads and measuring transport [10,25,44,45]. The signatures of FMFs will be present in the differential conductance measurement by the fulfillment of the Floquet sum rule [46].…”

Reprint of : Floquet Majorana fermions in superconducting quantum dots

“…The existence of these exotic dynamical quasiparticles can be detected by connecting two metallic leads and measuring transport [10,25,44,45]. The signatures of FMFs will be present in the differential conductance measurement by the fulfillment of the Floquet sum rule [46].…”

“…In the case of a triple QD, assuming 23 . In the case where μ 2 or μ 3 are zero the MFs are spatially separated [25]. Interestingly, the manipulation of the onsite-energies allows us to change the localization of the MFs, which would be relevant for their detection in transport [10].…”

Charge Transport Properties of the Majorana Zero Mode Induced Noncollinear Spin Selective Andreev Reflection*

“…There are a number of methods that have been used to generate and detect the MZM in condensed matter systems, [5,7−9] these include a chiral p-wave superconductor, [10] the 𝜈 = 5/2 fractional quantum Hall system, [1,2] topological insulator (TI)/swave superconductor (SC) interfaces with the MZM in the vortex core, [11] proximity-induced superconductors for spin-orbit coupled nanowires, [6,12] and a triple-quantum dot system. [13] An electron with its spin direction aligned with the MZM will undergo an Andreev reflection, while an electron with opposite spin direction will not. [14−18] This allows us to detect the existence of the MZM using ferromagnetic STM.…”