Transport Studies Of Local Gate Defined Quantum Dots In Nanowires
DOWNLOAD
Download Transport Studies Of Local Gate Defined Quantum Dots In Nanowires PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Transport Studies Of Local Gate Defined Quantum Dots In Nanowires book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Transport Studies Of Local Gate Defined Quantum Dots In Nanowires
DOWNLOAD
Author : Carina Fasth
language : en
Publisher:
Release Date : 2007
Transport Studies Of Local Gate Defined Quantum Dots In Nanowires written by Carina Fasth and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007 with categories.
Numerical Studies Of Transport And Anisotropic Exchange Interaction In Inas Nanowires
DOWNLOAD
Author : Nupur Gupta
language : en
Publisher:
Release Date : 2012
Numerical Studies Of Transport And Anisotropic Exchange Interaction In Inas Nanowires written by Nupur Gupta and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
High spin-orbit coupling and low effective mass of electrons in InAs nanowires makes it an attractive material for studying quantum physics in mesoscopic and nanoscale quantum devices. We first study the transport properties of FET devices made of InAs nanowires of diameter in the range of 35-70 nm. The temperature dependence of electron mobility in InAs nanowires from 10-200 K exhibits a positive slope below approximately 0 K, then turns over to a negative slope at higher temperatures. This is explained by Coulomb scattering from the surface donor like states that give rise to a subsurface accumulation layer and the thermal activation of these surface donors. The scattering rates are calculated using a momentum relaxation time approximation. The transition probabilities between the self-consistent Poisson-Schrodinger states of a 50 nm diameter nanowire are calculated using Fermi's golden rule. The results clarify the dominant scattering mechanism in InAs nanowires and signify the need for surface passivation to obtain high mobility devices. In a second study, we model a gate defined double quantum dot in the nanowire with high spin-orbit coupling in order to determine the precise gate voltage dependence of the exchange Hamiltonian. This modelling is critical for designing two-qubit quantum logic operations in the nanowire double dot architecture. A quantum double well structure is simulated based on the realistic potential created by a set of fine local electrostatic gates in the presence of nanowire surface accumulation layer. An effective spin Hamiltonian is derived for a pair of interacting electrons localized in the double dot system in the presence of a strong spin-orbit coupling. The accuracy of the effective Hamiltonian is established by a strong agreement obtained between the dynamics generated by the effective Hamiltonian with those obtained by a numerically exact solution of the time-dependent Schrodinger equation. The parametric dependences of the effective exchange Hamiltonian on external magnetic field, barrier gate voltage, and spin-orbit field is determined. This opens the door to designing optimal pulses for high fidelity quantum gates in real InAs nanowire devices.
Numerical Studies Of Transport And Spin Orbit Exchange In Inas Nanowires
DOWNLOAD
Author : Nupur Gupta
language : en
Publisher:
Release Date : 2013
Numerical Studies Of Transport And Spin Orbit Exchange In Inas Nanowires written by Nupur Gupta and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Electron Transport In Semiconducting Nanowires And Quantum Dots
DOWNLOAD
Author : Gregory Holloway
language : en
Publisher:
Release Date : 2017
Electron Transport In Semiconducting Nanowires And Quantum Dots written by Gregory Holloway and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with Nanowires categories.
Single electrons confined in electrostatic quantum dots are a promising platform for realizing spin based quantum information processing. In this scheme, the spin of each electron is encoded as a qubit, and can be manipulated and measured by modulating the gate voltages defining each dot. Since each qubit is realized in a single quantum dot, one could imagine scaling up this system by placing many quantum dots together in a tightly packed array. To be truly scalable each qubit must exhibit minimal variation, such that their behavior is consistent across the entire device. Transport through these quantum dots must therefore be explored in detail, to determine the source of these variations and design strategies to combat their effects. In this thesis a study of the transport properties of InAs nanowires and Si quantum dots is presented. In both systems the close proximity of the conduction electrons to defect-prone surfaces or interfaces causes them to be very sensitive to the physical properties of these regions. Through cryogenic transport measurements, and the development of relevant physical models, the effects of surface states, oxide charge traps, and interface defects are explored. In general these defects possess a finite charge, which modifies the electrostatic potential and alters electron transport. These additional changes to the electrostatic potential are detrimental for spin based quantum information processing, which requires precise control of this potential. In addition, the severity of each of these effects can be different in each device, leading to variation which limits scalability. By studying these effects we aim to better understand their properties and origins, such that they can be mitigated. Static defects, such as surface states, are found to be a dominant source of scattering that limits mobility. In InAs nanowires, we find that these effects can be removed through growth of an epitaxial shell that physically separates the nanowire surface from the conducting core. Dynamic defects on the other hand, lead to charge noise that shifts the potential causing instability. This noise originates from charge traps in close proximity to the conduction channel. For nanowires, the native oxide that forms at the surface is a likely location for these traps to occur. Through removal of this oxide and replacement with a defect free dielectric shell, greatly improved stability is observed. To test the viability of these fabrication techniques, nanowires treated with the most promising surface processes are used to fabricate top-gated nanowire field effect transistors. These devices are used to realize electrostatically defined double quantum dots, which show well controlled transport properties and minimal charge noise. In Si, electron transport is studied in a pair of capacitively coupled metal-oxide-semiconductor quantum dots. Here, the capacitive coupling is used implement charge sensing, such that the electrostatic potential of one dot can be measured down to the single electron regime. The pair of dots is also used to implement a novel memristive system which demonstrates current hysteresis. This shows the versatility of this system and its capability to control individual electrons, similar to the requirements needed to implement spin based quantum information processing.
Quantum Dots And Nanowires
DOWNLOAD
Author : Supriyo Bandyopadhyay
language : en
Publisher:
Release Date : 2003
Quantum Dots And Nanowires written by Supriyo Bandyopadhyay and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Science categories.
Quantum Dots and Nanowires provides coverage on various emerging aspects of quantum dots and nanowires. This book covers recent advances in physical and chemical synthetic approaches, processing and fabrication of semiconductor quantum-dot arrays, superlattices, self-assemblies, nanowires, nanotubes and nanobelts, computational modeling approaches, spectroscopic characterization, their unique electrical, optical, magnetic and physical properties associated with size effect, transport phenomena, quantum computing, and other potential applications.
Quantum Transport In Inas Nanowires With Etched Constrictions And Local Side Gating
DOWNLOAD
Author : Yao Ma
language : en
Publisher:
Release Date : 2012
Quantum Transport In Inas Nanowires With Etched Constrictions And Local Side Gating written by Yao Ma and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Fingerprints In The Optical And Transport Properties Of Quantum Dots
DOWNLOAD
Author : Ameenah Al-Ahmadi
language : en
Publisher: IntechOpen
Release Date : 2012-06-13
Fingerprints In The Optical And Transport Properties Of Quantum Dots written by Ameenah Al-Ahmadi and has been published by IntechOpen this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-06-13 with Science categories.
The book "Fingerprints in the optical and transport properties of quantum dots" provides novel and efficient methods for the calculation and investigating of the optical and transport properties of quantum dot systems. This book is divided into two sections. In section 1 includes ten chapters where novel optical properties are discussed. In section 2 involve eight chapters that investigate and model the most important effects of transport and electronics properties of quantum dot systems This is a collaborative book sharing and providing fundamental research such as the one conducted in Physics, Chemistry, Material Science, with a base text that could serve as a reference in research by presenting up-to-date research work on the field of quantum dot systems.
Transport In Nanostructures
DOWNLOAD
Author : David K. Ferry
language : en
Publisher: Cambridge University Press
Release Date : 2009-08-20
Transport In Nanostructures written by David K. Ferry and has been published by Cambridge University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009-08-20 with Science categories.
The advent of semiconductor structures whose characteristic dimensions are smaller than the mean free path of carriers has led to the development of novel devices, and advances in theoretical understanding of mesoscopic systems or nanostructures. This book has been thoroughly revised and provides a much-needed update on the very latest experimental research into mesoscopic devices and develops a detailed theoretical framework for understanding their behaviour. Beginning with the key observable phenomena in nanostructures, the authors describe quantum confined systems, transmission in nanostructures, quantum dots, and single electron phenomena. Separate chapters are devoted to interference in diffusive transport, temperature decay of fluctuations, and non-equilibrium transport and nanodevices. Throughout the book, the authors interweave experimental results with the appropriate theoretical formalism. The book will be of great interest to graduate students taking courses in mesoscopic physics or nanoelectronics, and researchers working on semiconductor nanostructures.
Quantum Transport Through Nanostructures
DOWNLOAD
Author : Daniel Boese
language : en
Publisher:
Release Date : 2002
Quantum Transport Through Nanostructures written by Daniel Boese and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Nanowires categories.
Transport In Nanowire Based Quantum Dot Systems
DOWNLOAD
Author : Sven Dorsch
language : en
Publisher:
Release Date : 2022
Transport In Nanowire Based Quantum Dot Systems written by Sven Dorsch and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.
Quantum dots embedded in an electronic circuit allow precise control over the charge transport behaviour of the system: Charge carriers can be individually trapped or precisely shuffled between a series of quantum dots in a strictly sequential manner. This introduces ideal conditions to study fundamental quantum physics and such devices are in the focus of extensive efforts to develop quantum information related applications. This thesis contributes to the development of model systems enabling control of, and abiding by quantum mechanical effects. The aim of the model systems is to search and use advantages compared to devices governed purely by the laws of classical physics. In this thesis, transport phenomena in n- and p-type III-V semiconductor nanowire quantum dot systems are explored. First, the concepts necessary to build an understanding of charge transport across quantum dot systems, namely quantum confinement in nanostructures and Coulomb blockade, are introduced. Next, the principles of transport across single and double quantum dot devices are discussed and various experimental device designs are presented. The experimental work falls into two separate research directions and the thesis includes three published papers, which are put into context and supplemented with additional experimental results. Paper I characterizes the properties of p-type GaSb nanowires to assess the material's applicability for the realization of spin-orbit qubits as fundamental building blocks of solid state quantum computers. Experimentally, g-factors and the spin-orbit energy are determined and fabricational challenges for the realization of serial double quantum dot devices are discussed and overcome. Papers II and III study thermally driven currents in InAs nanowire double quantum dots, where heat is essentially converted to electrical power. Such nanoscale energy harvesters operate in a regime where fluctuations are highly relevant and give insights into fundamental nanothermodynamic concepts. Thermally induced currents in double quantum dot devices are the result of three-terminal phonon-assisted transport or the two-terminal thermoelectric effect. Paper II studies the interplay of the two effects, the relevance of the interdot coupling and the impact of excited states. Paper III develops a versatile device architecture which combines bottom-gating and heating and enables the localized application of heat along the nanowire axis. Such devices provide ideal, controlled conditions for future studies of fundamental nanothermodynamics.