Electrostatic formation of the Majorana quasiparticles in the quantum dot-nanoring structure

Abstract

Zero-energy Majorana quasiparticles can be induced at the edge of a low dimensional systems. Non-Abelian statistics of this state makes it a good candidate for the realization of quantum computing. From the practical point of view, it is crucial to obtain an intentional creation and manipulation of this type of bound states. Here, we show such a possibility in a setup of quantum nanoring in which we specify a quantum dot region via electrostatic means. States in such quantum dot can lead to the emergence of Andreev and Majorana bound states in investigated system. We study the differences between those bound states and the possibility of their manipulation. Moreover, exact calculation method for spectral function has been proposed, which can be used to discuss the bound states influence on band structure of proposed system. Using this method, it can be shown that the Majorana bound states, induced at the edge of the system, present themselves as a dispersionless zero-energy band. *

Influence of long-range interaction on Majorana zero modes

“…In general, the overlap Ω can be controlled by some parameter modification, like electrostatic potential [72][73][74][75] or inter-site interactions [57,62]. In our case, we control…”

Delocalisation of Majorana quasiparticles in plaquette–nanowire hybrid system

“…Emergence of the degenerate Majorana modes from the Andreev bound states has been also reported in hybrid structures, comprising the quantum dots side-attached to the topological superconducting nanowires [7]. Initial theoretical prediction of such MBS leakage on the quantum dot region [26] has been investigated by various groups [27][28][29][30][31][32][33][34][35]. In these hybrid structures the wavefunction of Majorana quasiparticle is spread onto a region of the normal quantum dot-superconducting nanowire interface [20,24,[35][36][37][38], diluting the spatial distribution of its spectral weight.…”

“…In one-dimensional structures the Majorana quasiparticles localise at the sample boundaries [40] or near internal defects [32,41,42]. Contrary to that, for quasi two-dimensional systems there have been predicted chiral edge modes [43][44][45][46] enabling the Majoranas to be delocalised, both in the real and momentum spaces [32]. Evidence for such dispersive Majorana modes have been recently provided by STM measurements for magnetic islands deposited on superconducting substrates [47][48][49][50].…”

Dimerization-induced topological superconductivity in a Rashba nanowire

“…Electron pairing of these one-dimensional systems is driven via the proximity effect whereas the topological phase originates either (a) from the spin-orbit coupling (SOC) combined with a sufficiently strong Zeeman field [19][20][21][22][23] or (b) from spiral magnetic textures [24][25][26][27][28][29][30][31][32][33]. In both cases MZMs are localized on the most peripheral sites of such nanowires or nanochains [34][35][36][37][38][39] or separated by an artificial barrier [40]. Their robustness against various types of perturbations has been extensively explored, considering e.g.…”