Signatures of Majorana States in Electron Transport through a Quantum Dot Coupled to a Topological Wire

Abstract

We consider theoretically a system composed of a quantum dot coupled to a topological superconducting wire. The dot, being in Coulomb blockade (CB) regime is additionally coupled to the normal leads. The topological wire hosts Majorana states, which, as we show, characteristically modies conductance through the dot. An unpaired Majorana state in the wire causes a unique temperature dependence of zero bias conductance vs. gate voltage. It decreases in-between CB peaks and on the sides of the peaks from the plateau at ∼ e 2 /2h when temperature increases. At the same time conductance increases at the CB peak positions. It is accompanied by zero bias anomaly in dierential conductance. For nite overlap of Majorana states in the wire the zero bias anomaly disappears. Instead, two characteristic Fano resonances of opposite symmetry appear, positioned mirror-symmetrically with respect to zero bias.

Quantum transport through a quantum dot side-coupled to a Majorana bound state pair in the presence of electron-phonon interaction

“…12(a) and (c)]. Moreover, the maximum of G grows with T and is suppressed again at higher temperatures in agreement with the literature [36,48]. For larger values of |λ| the conductance peaks are broadened at high T but are more narrow in contrast to the case of weak coupling |λ|.…”

“…In the past years, numerous QDs-MBSs devices have been proposed to detect the signature of MBSs by probing their transport properties such as the conductance spectrum [32][33][34][35][36][37], current noise [32,[38][39][40][41][42][43], thermal conductance [44][45][46][47][48], photon-assisted [49][50][51], Josephson effect [52] and Fano resonance [53][54][55][56][57][58][59][60][61][62][63]. Zeng et al [58] analyzed the transport inside a ring system formed by an asymmetrically biased QD coupled to two MBSs located at the end of a TSNW.…”

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

“…1). In the case when both external leads are metallic it has been predicted reduction (by half) of the quantum dot conductance 32 , suppression of the Seebeck coefficient (due to perfect particle-hole symmetry at the Fermi level) 33 and unique interferometric lineshapes [34][35][36][37][38][39] .…”

Spin Dependent Conductance of a Quantum Dot Side attached to Topological Superconductors as a Probe of Majorana Fermion States

“…carbon nanotubes with broken chiral symmetry and curvature induced spin-orbit coupling [4]. Various proposals have been made to detect the Majorana states using different hybrid structures based on quantum dots [5,6]. In this report we discuss signatures of Majorana states in transport through quantum dot coupled to normal leads and to a single or a pair of TS wires.…”