Transport properties of a quantum dot and a quantum ring in series

2018 ◽  
Vol 72 (1) ◽  
pp. 138-143 ◽  
Author(s):  
Minky Seo ◽  
Yunchul Chung
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Quantum Ring ◽  
In Series

scholarly journals Quantum dot–ring nanostructure — A comparison of different approaches

2016 ◽  
Vol 30 (13) ◽  
pp. 1642013 ◽  
Author(s):  
Iwona Janus-Zygmunt ◽  
Barbara Kȩdzierska ◽  
Anna Gorczyca-Goraj ◽  
Elżbieta Zipper ◽  
Maciej M. Maśka
Keyword(s):  
Quantum Dot ◽  
Schrödinger Equation ◽  
Transport Properties ◽  
Schrodinger Equation ◽  
Cylindrical Symmetry ◽  
Two Dimensions ◽  
Quantum Ring ◽  
Tight Binding Approximation ◽  
The Third ◽  
Confining Potential

It has been shown recently that a nanostructure composed of a quantum dot (QD) surrounded by a quantum ring (QR) possesses a set of very unique characteristics that make it a good candidate for future nanoelectronic devices. Its main advantage is the ability to easily tune transport properties on demand by so-called “wavefunction engineering”. In practice, the distribution of the electron wavefunction in the nanostructure can be controlled by, e.g., electrical gating. In order to predict some particular properties of the system, one has to know the exact wavefunctions for different shapes of the confining potential that defines the structure. In this paper, we compare three different methods that can be used to determine the energy spectrum, electron wavefunctions and transport properties of the system under investigation. In the first approach, we utilize the cylindrical symmetry of the confining potential and solve only the radial part of the Schrödinger equation; in the second approach, we discretize the Schrödinger equation in two dimensions and find the eigenstates with the help of the Lanczös method; in the third approach, we use package Kwant to solve a tight-binding approximation of the original system. To study the transport properties in all these approaches, we calculate microscopically the strength of the coupling between the nanosystem and leads. In the first two approaches, we use the Bardeen method, in the third one calculations are performed with the help of package Kwant.

scholarly journals Topological isoconductance signatures in Majorana nanowires

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
L. S. Ricco ◽  
J. E. Sanches ◽  
Y. Marques ◽  
M. de Souza ◽  
M. S. Figueira ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Spin Polarization ◽  
Bound States ◽  
Spin Asymmetry ◽  
Experimental Protocol ◽  
Zero Bias ◽  
Topological Superconductor ◽  
Hybrid Device ◽  
Majorana Bound States

AbstractWe consider transport properties of a hybrid device composed by a quantum dot placed between normal and superconducting reservoirs, and coupled to a Majorana nanowire: a topological superconducting segment hosting Majorana bound states (MBSs) at the opposite ends. It is demonstrated that if highly nonlocal and nonoverlapping MBSs are formed in the system, the zero-bias Andreev conductance through the dot exhibits characteristic isoconductance profiles with the shape depending on the spin asymmetry of the coupling between the dot and the topological superconductor. Otherwise, for overlapping MBSs with less degree of nonlocality, the conductance is insensitive to the spin polarization and the isoconductance signatures disappear. This allows to propose an alternative experimental protocol for probing the nonlocality of the MBSs in Majorana nanowires.

Magneto-transport properties of InAs/AlGaSb open quantum dot structures

2002 ◽  
Vol 314 (1-4) ◽  
pp. 481-485 ◽  
Author(s):  
T. Maemoto ◽  
T. Kobayashi ◽  
T. Karasaki ◽  
K. Kita ◽  
S. Sasa ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Open Quantum

scholarly journals Effect of confinement potential shape on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot at finite temperature

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
K. Luhluh Jahan ◽  
Bahadir Boyacioglu ◽  
Ashok Chatterjee
Keyword(s):  
Magnetic Field ◽  
Heat Capacity ◽  
Quantum Dot ◽  
Transport Properties ◽  
Average Energy ◽  
Persistent Current ◽  
Confinement Potential ◽  
Potential Shape ◽  
Gaas Quantum Dot ◽  
The Magnetic Field

Abstract The effect of the shape of the confinement potential on the electronic, thermodynamic, magnetic and transport properties of a GaAs quantum dot is studied using the power-exponential potential model with steepness parameter p. The average energy, heat capacity, magnetic susceptibility and persistent current are calculated using the canonical ensemble approach at low temperature. It is shown that for soft confinement, the average energy depends strongly on p while it is almost independent of p for hard confinement. The heat capacity is found to be independent of the shape and depth of the confinement potential at low temperatures and for the magnetic field considered. It is shown that the system undergoes a paramagnetic-diamagnetic transition at a critical value of the magnetic field. It is furthermore shown that for low values of the potential depth, the system is always diamagnetic irrespective of the shape of the potential if the magnetic field exceeds a certain value. For a range of the magnetic field, there exists a window of p values in which a re-entrant behavior into the diamagnetic phase can occur. Finally, it is shown that the persistent current in the present quantum dot is diamagnetic in nature and its magnitude increases with the depth of the dot potential but is independent of p for the parameters considered.

Phase Relaxation and Non-Equilibrium Transport Properties through Multilevel Quantum Dot

1999 ◽  
Vol 38 (Part 1, No. 1B) ◽  
pp. 388-391 ◽  
Author(s):  
Yasuhiro Funabashi ◽  
Kazuhiko Ohtsubo ◽  
Mikio Eto ◽  
Kiyoshi Kawamura
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Phase Relaxation ◽  
Non Equilibrium

Thermoelectric Transport in Sb2Te3/Bi2Te3 Quantum Dot Nanocomposites

2011 ◽  
Author(s):  
J. Zhou ◽  
R. G. Yang
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
High Efficiency ◽  
Phonon Scattering ◽  
Transport Model ◽  
Binding Model ◽  
Thermoelectric Transport ◽  
Bottleneck Effect ◽  
Phonon Bottleneck ◽  
Thermoelectric Transport Properties

We investigate the thermoelectric transport properties of Sb2Te3/Bi2Te3 quantum dot nanocomposites with spherical Sb2Te3 quantum dots arrays embedded in Bi2Te3 matrix through a two-channel transport model. In this model, the transport of quantum-confined electrons through the hopping mechanism is studied by tight-binding model together with Kubo formula and Green’s function method. The formation of minibands due to the quantum confinement and the phonon-bottleneck effect on carrier-phonon scattering are considered. The transport of bulk-like electrons is studied by Boltzmann-transport-equation-based model. We consider the intrinsic carrier scatterings as well as the carrier-interface scattering of these bulk-like electrons. Thermoelectric transport properties are studied with different quantum dot sizes, inter-dot distances, doping concentrations, and temperatures. We find that electrical conductivity and Seebeck coefficient can be enhanced simultaneously in Sb2Te3/Bi2Te3 quantum dot nanocomposites because of the formation of minibands and the phonon-bottleneck effect on carrier-phonon scattering. Our results could shed some light on the design of high-efficiency thermoelectric materials.

Eigenenergies and quantum transport properties in a non-Hermitian quantum-dot chain with side-coupled dots

2019 ◽  
Vol 99 (3) ◽  
Author(s):  
Lian-Lian Zhang ◽  
Ze-Zhong Li ◽  
Guo-Hui Zhan ◽  
Guang-Yu Yi ◽  
Wei-Jiang Gong
Keyword(s):  
Quantum Dot ◽  
Transport Properties ◽  
Quantum Transport
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