Spin-polarized quantum transport through a quantum dot in time-varying magnetic field

The influence of time-varying fields on the transport through a mesoscopic device has been investigated. This mesoscopic device is modeled as a quantum dot coupled to superconducting reservoirs via quantum point contact. The effect of a magnetic field and the Andreev reflection process were taken into account. The conductance was deduced by using Landuaer–Buttiker equation. A numerical calculation has been performed that shows a resonant tunneling behavior. Such investigation is important for fabricating photoelectron mesoscopic devices.

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Spin-polarized current diode effect of a quantum dot in a rotating magnetic field

Physica Scripta ◽

10.1088/0031-8949/78/06/065703 ◽

2008 ◽

Vol 78 (6) ◽

pp. 065703 ◽

Cited By ~ 2

Author(s):

Hui Pan

Keyword(s):

Magnetic Field ◽

Quantum Dot ◽

Rotating Magnetic Field ◽

Spin Polarized

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Spin-polarized quantum transport and magnetic field-dependent carrier density in magnetic two-dimensional electron gases

Physica E Low-dimensional Systems and Nanostructures ◽

10.1016/s1386-9477(99)00238-6 ◽

2000 ◽

Vol 6 (1-4) ◽

pp. 786-789 ◽

Cited By ~ 11

Author(s):

R Knobel ◽

N Samarth ◽

S.A Crooker ◽

D.D Awschalom

Keyword(s):

Magnetic Field ◽

Quantum Transport ◽

Carrier Density ◽

Two Dimensional ◽

Dimensional Electron ◽

Electron Gases ◽

Spin Polarized ◽

Field Dependent

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PUMPING CURRENT IN A QUANTUM DOT BY AN OSCILLATING MAGNETIC FIELD

International Journal of Modern Physics B ◽

10.1142/s0217979207045542 ◽

2007 ◽

Vol 21 (23n24) ◽

pp. 4284-4288 ◽

Cited By ~ 1

Author(s):

ZHAO YANG ZENG ◽

HONG LI ◽

BAOWEN LI

Keyword(s):

Magnetic Field ◽

Quantum Dot ◽

Current Flow ◽

Spin Current ◽

Rate Equations ◽

Time Varying ◽

Charge Current ◽

Occupation Numbers ◽

Experimental Parameters ◽

Oscillating Magnetic Field

We investigate spin and charge current through a quantum dot pumped by a time-varying magnetic field. Using the density matrix method, quantum rate equations for the electronic occupation numbers in the quantum dot are obtained and solved in the stationary state limit for a wide set of parameters. Both charge and spin currents are expressed explicitly in terms of several relevant parameters and analyzed in detail. The results suggest a way of optimizing experimental parameters to obtain an maximal spin current without the charge current flow.

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Spin filtering and magnetically-controlled quantum switch in multiple triangular rings consisting of quantum dots

Modern Physics Letters B ◽

10.1142/s0217984921501773 ◽

2021 ◽

pp. 2150177

Author(s):

Jiyuan Bai ◽

Xiaoyu Li ◽

Xiaofeng Peng ◽

Yunfeng Bai ◽

Kongfa Chen ◽

...

Keyword(s):

Magnetic Field ◽

Quantum Dots ◽

Quantum Dot ◽

Coulomb Interactions ◽

Quantum Devices ◽

Resonance Point ◽

Conductance Spectrum ◽

Spin Polarized ◽

Non Equilibrium Green’S Function ◽

Spin Filtering

Electron transport characteristics through a system consisting of a series of triangular quantum dot rings are studied utilizing the non-equilibrium Green’s function. In the presence of a magnetic field, an additional anti-resonance point occurs in the conductance spectrum. As the number of triangular quantum dot rings increases, two anti-resonance points evolve into two well-defined insulating bands. The insulating band disappears as the magnetic flux takes an appropriate value, and therefore, an effective magnetically-controlled quantum switch can be achieved. If a Zeeman magnetic field is introduced, a spin-polarized window (SPW) can be formed, suggesting a physical scheme of a spin filtering. As the intradot Coulomb interactions are taken into consideration, more SPWs can be obtained. This work sheds lights onto the design of future quantum devices.

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Pumping Spin and Charge Currents from Applying a Time-Variant Field and a Magnetic Field to a Quantum Dot

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.480-481.1446 ◽

2011 ◽

Vol 480-481 ◽

pp. 1446-1451

Author(s):

Jian Ming Yao

Keyword(s):

Magnetic Field ◽

Quantum Dot ◽

Bias Voltage ◽

Evolution Operator ◽

Operator Approach ◽

Zero Bias ◽

Spin Pumping ◽

Spin Polarized ◽

The Magnetic Field

Photon-electron pumping effects on a quantum dot connected to two magnetic leads in the presence of both via-dot and over-dot tunneling channels have been investigated by the evolution operator approach. It is found that a time-variant field applied to the quantum dot may give rise to charge and spin pumping at zero bias voltage for asymmetric magnetic junctions. When the magnetic field switch on，the spin-up and spin-down current can be considerably separated，then the highly spin polarized current is also generated.

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