THEORETICAL INVESTIGATIONS OF QUANTUM TRANSPORT THROUGH CARBON NANOTUBE DEVICES

2000 ◽  
Vol 07 (05n06) ◽  
pp. 637-642 ◽  
Author(s):  
C. ROLAND ◽  
M. BUONGIORNO NARDELLI ◽  
H. GUO ◽  
H. MEHREZ ◽  
J. TAYLOR ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Quantum Transport ◽  
Function Analysis ◽  
Tight Binding ◽  
Spin Valve ◽  
Superconducting Devices ◽  
Binding Model ◽  
Theoretical Investigations ◽  
Carbon Nanotube Devices

By combining a nonequilibrium Green's function analysis with a standard tight-binding model, we have investigated quantum transport through carbon nanotube devices. For finite-sized nanotubes, transport is dominated by resonant tunneling, with the conductance being strongly dependent on the length of the nanotubes. Turning to nanotube devices, we have investigated spin-coherent transport in ferromagnetic–nanotube–ferromagnetic devices and nanotube-superconducting devices. The former shows a significant spin valve effect, while the latter is dominated by resonant Andreev reflections. In addition, we discuss AC transport through carbon nanotubes and the role of photon-assisted tunneling.

scholarly journals Enabling Large-Scale Simulations of Quantum Transport with Manycore Computing

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 253
Author(s):  
Yosang Jeong ◽  
Hoon Ryu
Keyword(s):  
Quantum Transport ◽  
Large Scale ◽  
Performance Enhancement ◽  
Silicon Nanowire ◽  
Matrix Multiplication ◽  
Tight Binding ◽  
Optimization Techniques ◽  
Wide Energy Range ◽  
Processing Unit ◽  
Binding Model

The non-equilibrium Green’s function (NEGF) is being utilized in the field of nanoscience to predict transport behaviors of electronic devices. This work explores how much performance improvement can be driven for quantum transport simulations with the aid of manycore computing, where the core numerical operation involves a recursive process of matrix multiplication. Major techniques adopted for performance enhancement are data restructuring, matrix tiling, thread scheduling, and offload computing, and we present technical details on how they are applied to optimize the performance of simulations in computing hardware, including Intel Xeon Phi Knights Landing (KNL) systems and NVIDIA general purpose graphic processing unit (GPU) devices. With a target structure of a silicon nanowire that consists of 100,000 atoms and is described with an atomistic tight-binding model, the effects of optimization techniques on the performance of simulations are rigorously tested in a KNL node equipped with two Quadro GV100 GPU devices, and we observe that computation is accelerated by a factor of up to ∼20 against the unoptimized case. The feasibility of handling large-scale workloads in a huge computing environment is also examined with nanowire simulations in a wide energy range, where good scalability is procured up to 2048 KNL nodes.

scholarly journals The role of quantum interference in determining transport properties of molecular bridges

2004 ◽  
Vol 2 (3) ◽  
pp. 524-533 ◽  
Author(s):  
Kamil Walczak
Keyword(s):  
Quantum Interference ◽  
Molecular System ◽  
Tight Binding ◽  
Transmission Function ◽  
Molecular Devices ◽  
Binding Model ◽  
Quantum Interference Effect ◽  
Current Voltage ◽  
Essential Question

AbstractAn analytical approach to the electron transport phenomena in molecular devices is presented. The analyzed devices are composed of various molecular bridges attached to two semi-infinite electrodes. Molecular system is described within the tight-binding model, while the coupling to the electrodes is analyzed through the use of Newns-Anderson chemisorption theory. The current-voltage (I-V) characteristics are calculated through the integration of transmission function in the standard Landauer formulation. The essential question of quantum interference effect of electron waves is diseussed in three aspects: (i) the geometry of a molecular bridge, (ii) the presence of an external magnetic field and (iii) the location of chemical substituent.

Tight-binding molecular dynamics study of the role of defects on carbon nanotube moduli and failure

2007 ◽  
Vol 127 (7) ◽  
pp. 074708 ◽  
Author(s):  
Richard W. Haskins ◽  
Robert S. Maier ◽  
Robert M. Ebeling ◽  
Charles P. Marsh ◽  
Dustin L. Majure ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Tight Binding

scholarly journals QUANTUM TRANSPORT THROUGH SINGLE PHENALENYL MOLECULE: EFFECT OF INTERFACE STRUCTURE

2007 ◽  
Vol 06 (06) ◽  
pp. 415-422 ◽  
Author(s):  
SANTANU K. MAITI
Keyword(s):  
Quantum Transport ◽  
Electronic Transport ◽  
Coupling Strength ◽  
Tight Binding ◽  
Interface Structure ◽  
Function Technique ◽  
Tight Binding Model ◽  
Parametric Approach ◽  
Binding Model ◽  
Molecular Bridge

The electronic transport characteristics through a single phenalenyl molecule sandwiched between two metallic electrodes are investigated by using Green's function technique. A parametric approach, based on the tight-binding model, is used to study the transport characteristics through such molecular bridge system. The electronic transport properties are significantly influenced by (a) the molecule-to-electrodes interface structure and (b) the molecule-to-electrodes coupling strength.

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