Erasable signature of Majorana bound state due to coupling with the T-shaped quantum-dot structure

TL;DR

This paper investigates how Majorana bound states influence electron transport in a T-shaped double quantum-dot system, revealing conditions under which the MBS signature appears or is suppressed in conductance measurements.

Contribution

It introduces a theoretical analysis of the impact of Majorana bound states on transport in a T-shaped quantum-dot structure, highlighting the role of the side-coupled dot and inter-MBS coupling.

Findings

Majorana bound states cause conductance changes depending on the dot level.

The conductance remains at e^2/2h when the dot level is at zero energy.

Inter-MBS coupling can suppress the Majorana signature in conductance.

Abstract

We theoretically study the transport properties in the T-shaped double-quantum-dot structure, by introducing the Majorana bound state (MBS) to couple to the dot in the main channel. It is found that the side-coupled dot governs the effect of the MBS on the transport behavior. When its level is consistent with the energy zero point, the MBS contributes little to the conductance spectrum. Otherwise, the linear conductance exhibits notable changes according to the inter-MBS coupling manners. In the case of Majorana zero mode, the linear conductance value keeps equal to $e^2\over 2h$ when the level of the side-coupled dot departs from the energy zero point. However, the linear conductance is always analogous to the MBS-absent case once the inter-MBS coupling comes into play. These findings provide new information about the interplay between the MBSs and electron states in the quantum dots.