scholarly journals Spin-dependent transport through helical Aharonov-Bohm interferometer

2021 ◽  
Vol 2086 (1) ◽  
pp. 012198
Author(s):  
R A Niyazov ◽  
D N Aristov ◽  
V Yu Kachorovskii
Keyword(s):  
Magnetic Field ◽  
Quantum Computing ◽  
High Temperature ◽  
Magnetic Impurities ◽  
Edge States ◽  
Level Spacing ◽  
Transmission Coefficients ◽  
Spin Dependent Transport ◽  
Dependent Transport ◽  
Aharonov Bohm

Abstract We discuss spin-dependent transport via tunneling Aharonov-Bohm interferometer formed by helical edge states tunnel-coupled to helical leads. We focus on the experimentally relevant high-temperature case as compared to the level spacing and obtain the full 4×4 matrix of transmission coefficients in the presence of magnetic impurities. We show that spin conserving and spin-flip transmission coefficients of the setup can be effectively tuned by the magnetic flux. These features are attractive due to possible applications for spintronics, magnetic field detection, and quantum computing.

scholarly journals Coherent spin transport through helical edge states of topological insulator

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
R. A. Niyazov ◽  
D. N. Aristov ◽  
V. Yu. Kachorovskii
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Topological Insulator ◽  
Spin Transport ◽  
Magnetic Impurity ◽  
Quantum Calculations ◽  
Edge States ◽  
Level Spacing ◽  
Aharonov Bohm ◽  
Coherent Spin

AbstractWe study coherent spin transport through helical edge states of topological insulator tunnel-coupled to metallic leads. We demonstrate that unpolarized incoming electron beam acquires finite polarization after transmission through such a setup provided that edges contain at least one magnetic impurity. The finite polarization appears even in the fully classical regime and is therefore robust to dephasing. There is also a quantum magnetic field-tunable contribution to the polarization, which shows sharp identical Aharonov-Bohm resonances as a function of magnetic flux—with the period hc/2e—and survives at relatively high temperature. We demonstrate that this tunneling interferometer can be described in terms of ensemble of flux-tunable qubits giving equal contributions to conductance and spin polarization. The number of active qubits participating in the charge and spin transport is given by the ratio of the temperature and the level spacing. The interferometer can effectively operate at high temperature and can be used for quantum calculations. In particular, the ensemble of qubits can be described by a single Hadamard operator. The obtained results open wide avenue for applications in the area of quantum computing.

SPIN-DEPENDENT BEATS CREATED BY IRRADIATION OF MICROWAVE FIELD THROUGH A QUANTUM DOT

2011 ◽  
Vol 25 (25) ◽  
pp. 2033-2039
Author(s):  
M. BAGHERI TAGANI ◽  
H. RAHIMPOUR SOLEIMANI
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Microwave Field ◽  
Spin Current ◽  
Tunneling Magnetoresistance ◽  
Rate Equations ◽  
Spin Accumulation ◽  
Spin Dependent Transport ◽  
Field Temperature ◽  
Dependent Transport

We study spin-dependent transport through a quantum dot with Zeeman split levels coupled to ferromagnetic leads and under influence of microwave irradiation. Current polarization, spin current, spin accumulation and tunneling magnetoresistance are analyzed using nonequilibrium Green's function formalism and rate equations. Spin-dependent beats in spin resolved currents are observed. The effects of magnetic field, temperature and Coulomb interaction on these beats are studied.

scholarly journals Spin-dependent transport in a two-dimensional GaAs electron gas in a parallel magnetic field

2002 ◽  
Vol 12 (1-4) ◽  
pp. 412-415
Author(s):  
Yu-Ming Cheng ◽  
Tsai-Yu Huang ◽  
Chao Han Pao ◽  
Chun-Cheng Lee ◽  
C.-T Liang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Gas ◽  
Two Dimensional ◽  
Parallel Magnetic Field ◽  
Spin Dependent Transport ◽  
Dependent Transport

scholarly journals Enhanced magnetic field sensitivity of spin-dependent transport in cluster-assembled metallic nanostructures

2006 ◽  
Vol 5 (9) ◽  
pp. 730-734 ◽  
Author(s):  
Santiago Serrano-Guisan ◽  
Giulia di Domenicantonio ◽  
Mohamed Abid ◽  
Jean-Pierre Abid ◽  
Matthias Hillenkamp ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Metallic Nanostructures ◽  
Field Sensitivity ◽  
Spin Dependent Transport ◽  
Dependent Transport

Controllable Tuning of the Spin-Dependent Transport in the Graphene Sheet

2014 ◽  
Vol 668-669 ◽  
pp. 8-11
Author(s):  
Chun Mei Liu ◽  
Zhuan Li ◽  
Jun Ling Wang ◽  
Li Li Zhao ◽  
Yang Wang
Keyword(s):  
Density Functional Theory ◽  
Graphene Sheet ◽  
Density Functional ◽  
Edge States ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Spin Polarized ◽  
Dependent Transport ◽  
Non Equilibrium Green’S Function

Based on the non-equilibrium Green’s function in combination with the density-functional theory, The spin-dependent transport in the short graphene nanoribbon (graphene sheet) asymmetrically coupled to the electrodes of Au chains is investigated. It is found that a fully spin-polarized current (close to 100%) can be produced at the output port. The physics underlying attributes to the spatially separated edge states of the sheet caused by asymmetric contacts. Especially, the current's spin polarized direction can be tuned simply by changing the contact locations of the electrodes to the graphene sheet.

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