Download or read book Nonequilibrium Electron Transport in Quantum Dot and Quantum Point Contact Systems written by Anasuya Erin Krishnaswamy and published by . This book was released on 1999 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Much experimental research has been performed in the equilibrium regime on individual quantum dots and quantum point contacts (QPCs). The focus of the research presented here is electron transport in the nonequilibrium regime in coupled quantum dot and QPC systems fabricated on AlGaAs/GaAs material using the split gate technique. Near equilibrium magnetoconductance measurements were performed on a quantum dot and a QPC. Oscillations were seen in the conductance of the sensor which corresponded to Aharonov-Bohm oscillations in the quantum dot, to our knowledge the first such observation. Sudden jumps in the conductance of the QPC were observed under certain gate biases and under certain magnetic fields. When the gate biases and magnetic field were held constant and the conductance was observed over time, switching was observed with the form of a random telegraph signal (RTS). RTS switching is usually attributed to charging of a single impurity. However, in this case switching may have been due to tunneling via edge states in the dot. Nonequilibrium transport in single quantum dots was investigated. A knee or kink was observed in the current-voltage characteristics of two dots on different material. The bias conditions under which the knee occurred point to electron heating as the physical mechanism for the observed behavior. However, the data can not be fit accurately over all bias ranges with an energy balance hot electron model. Modifications to the model are needed to accurately represent the devices studied here. Finally, the effect of nonlinear transport through a one dimensional (1D) QPC on the equilibrium conductance of an adjacent OD quantum dot was explored. This was the first attempt to observe Coulomb drag between a OD and 1D system. It was observed that the equilibrium conductance peaks in the quantum dot were broadened as the current in the QPC increased. This apparent electron heating effect in the dot can be explained by a simple ballistic phonon model. However, reasonable phase coherence times can be estimated from peak fitting using a Breit- Wigner formula which points to a Coulomb interaction. More detailed numerical calculations should illuminate the dominant scattering processes.
Download or read book Non equilibrium Electron Transport Through a Double Quantum Dot System written by Verena Körting and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Electron Transport in Quantum Dots written by Jonathan P. Bird and published by Springer Science & Business Media. This book was released on 2013-11-27 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: When I was contacted by Kluwer Academic Publishers in the Fall of 200 I, inviting me to edit a volume of papers on the issue of electron transport in quantum dots, I was excited by what I saw as an ideal opportunity to provide an overview of a field of research that has made significant contributions in recent years, both to our understanding of fundamental physics, and to the development of novel nanoelectronic technologies. The need for such a volume seemed to be made more pressing by the fact that few comprehensive reviews of this topic have appeared in the literature, in spite of the vast activity in this area over the course of the last decade or so. With this motivation, I set out to try to compile a volume that would fairly reflect the wide range of opinions that has emerged in the study of electron transport in quantum dots. Indeed, there has been no effort on my part to ensure any consistency between the different chapters, since I would prefer that this volume instead serve as a useful forum for the debate of critical issues in this still developing field. In this matter, I have been assisted greatly by the excellent series of articles provided by the different authors, who are widely recognized as some of the leaders in this vital area of research.
Download or read book Nonequilibrium Statistical Physics of Small Systems written by Rainer Klages and published by John Wiley & Sons. This book was released on 2013-03-15 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a comprehensive picture of nonequilibrium phenomena in nanoscale systems. Written by internationally recognized experts in the field, this book strikes a balance between theory and experiment, and includes in-depth introductions to nonequilibrium fluctuation relations, nonlinear dynamics and transport, single molecule experiments, and molecular diffusion in nanopores. The authors explore the application of these concepts to nano- and biosystems by cross-linking key methods and ideas from nonequilibrium statistical physics, thermodynamics, stochastic theory, and dynamical systems. By providing an up-to-date survey of small systems physics, the text serves as both a valuable reference for experienced researchers and as an ideal starting point for graduate-level students entering this newly emerging research field.
Download or read book Quantum Transport Calculations for Nanosystems written by Kenji Hirose and published by CRC Press. This book was released on 2014-04-11 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: As electric devices become smaller and smaller, transport simulations based on the quantum mechanics become more and more important. There are currently numerous textbooks on the basic concepts of quantum transport, but few present calculation methods in detail. This book provides various quantum transport simulation methods and shows applications
Download or read book Electronic Interactions in Semiconductor Quantum Dots and Quantum Point Contacts written by Tai-Min Liu and published by . This book was released on 2011 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report several detailed experiments on electron transport through Quantum Point Contacts (QPCs) and lateral Quantum Dots (QDs), created in a Single-Electron Transistor (SET). In the experiment for QPCs, we present a zero-bias peak (ZBP) in the differential conductance, G, which splits in an external magnetic field. The observed splitting closely matches the Zeeman energy and shows very little dependence on gate voltage, suggesting that the mechanism responsible for the formation of the peak involves electron spin. We also show that the mechanism that leads to the formation of the ZBP is different from the conventional Kondo effect found in QDs. In the second experiment, we present transport measurements of a QD in a spin-flip cotunneling regime and a quantitative comparison of the data to the microscopic theory by Lehman and Loss. The differential conductance is measured in the presence of an in-plane Zeeman field. We focus on the ratio of the nonlinear G at bias voltages exceeding the Zeeman threshold to G for those below the threshold. The data show good quantitative agreement with the theory with no adjustable parameters. We also compare the theoretical results to the predictions of a phenomenological form used for the determination of a heterostructure g-factor and find good agreement between the two. In the third experiment, we report the magnetic splitting, [Delta] K, of a Kondo peak in G for a QD while tuning the Kondo temperature, TK, along two different paths in the parameter space: varying the dot-lead coupling at a constant dot energy, and vice versa. At a high magnetic field, B, the changes of [Delta] K with TK along the two paths have opposite signs, indicating that [Delta] K is not a universal function of TK. At low B, we observe a decrease in [Delta]K with TK along both paths, in agreement with theoretical predictions. Furthermore, we find [Delta] K / [Delta]1 at low B and [Delta] K / [Delta] 1 at high B, where [Delta] is the Zeeman energy of the bare spin, in the same system. In the last experiment, we report the zero-bias differential conductance, of an SET in the Kondo regime as a function of temperature, T, and an in-plane magnetic field B. Scaled plots of both the T- and B-dependent data show universal behavior. At moderate and high B, the magnetoconductance data show good agreement with renormalization group calculations in the spin-1/2 Kondo regime. At very low B, we observe a non-monotonic behavior, which may due to the presence of multiple orbital dot levels with similar energies. Further study is required to confirm this assumption.
Download or read book Transport in Nanostructures written by David K. Ferry and published by Cambridge University Press. This book was released on 2009-08-20 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Mesoscopic Electron Transport written by Lydia L. Sohn and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ongoing developments in nanofabrication technology and the availability of novel materials have led to the emergence and evolution of new topics for mesoscopic research, including scanning-tunnelling microscopic studies of few-atom metallic clusters, discrete energy level spectroscopy, the prediction of Kondo-type physics in the transport properties of quantum dots, time dependent effects, and the properties of interacting systems, e.g. of Luttinger liquids. The overall understanding of each of these areas is still incomplete; nevertheless, with the foundations laid by studies in the more traditional systems there is no doubt that these new areas will advance mesoscopic electron transport to a new phenomenological level, both experimentally and theoretically. Mesoscopic Electron Transport highlights selected areas in the field, provides a comprehensive review of such systems, and also serves as an introduction to the new and developing areas of mesoscopic electron transport.
Download or read book Nanophysics Coherence and Transport written by and published by Elsevier. This book was released on 2005-08-02 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: The developments of nanofabrication in the past years have enabled the design of electronic systems that exhibit spectacular signatures of quantum coherence. Nanofabricated quantum wires and dots containing a small number of electrons are ideal experimental playgrounds for probing electron-electron interactions and their interplay with disorder. Going down to even smaller scales, molecules such as carbon nanotubes, fullerenes or hydrogen molecules can now be inserted in nanocircuits. Measurements of transport through a single chain of atoms have been performed as well. Much progress has also been made in the design and fabrication of superconducting and hybrid nanostructures, be they normal/superconductor or ferromagnetic/superconductor. Quantum coherence is then no longer that of individual electronic states, but rather that of a superconducting wavefunction of a macroscopic number of Cooper pairs condensed in the same quantum mechanical state. Beyond the study of linear response regime, the physics of non-equilibrium transport (including non-linear transport, rectification of a high frequency electric field as well as shot noise) has received much attention, with significant experimental and theoretical insights. All these quantities exhibit very specific signatures of the quantum nature of transport, which cannot be obtained from basic conductance measurements. Basic concepts and analytical tools needed to understand this new physics are presented in a series of theoretical fundamental courses, in parallel with more phenomenological ones where physics is discussed in a less formal way and illustrated by many experiments. · Electron-electron interactions in one-dimensional quantum transport· Coulomb Blockade and Kondo physics in quantum dots· Out of equilibrium noise and quantum transport· Andreev reflection and subgap nonlinear transport in hybrid N/S nanosructures.· Transport through atomic contacts · Solid state Q-bits · Written by leading experts in the field, both theorists and experimentalists
Download or read book Quantum Transport in Mesoscopic Systems written by David Sánchez and published by MDPI. This book was released on 2021-01-06 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mesoscopic physics deals with systems larger than single atoms but small enough to retain their quantum properties. The possibility to create and manipulate conductors of the nanometer scale has given birth to a set of phenomena that have revolutionized physics: quantum Hall effects, persistent currents, weak localization, Coulomb blockade, etc. This Special Issue tackles the latest developments in the field. Contributors discuss time-dependent transport, quantum pumping, nanoscale heat engines and motors, molecular junctions, electron–electron correlations in confined systems, quantum thermo-electrics and current fluctuations. The works included herein represent an up-to-date account of exciting research with a broad impact in both fundamental and applied topics.
Download or read book Open Quantum Systems Far from Equilibrium written by Gernot Schaller and published by Springer. This book was released on 2014-01-07 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph provides graduate students and also professional researchers aiming to understand the dynamics of open quantum systems with a valuable and self-contained toolbox. Special focus is laid on the link between microscopic models and the resulting open-system dynamics. This includes how to derive the celebrated Lindblad master equation without applying the rotating wave approximation. As typical representatives for non-equilibrium configurations it treats systems coupled to multiple reservoirs (including the description of quantum transport), driven systems and feedback-controlled quantum systems. Each method is illustrated with easy-to-follow examples from recent research. Exercises and short summaries at the end of every chapter enable the reader to approach the frontiers of current research quickly and make the book useful for quick reference.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory of Electron Transport in Semiconductors written by Carlo Jacoboni and published by Springer Science & Business Media. This book was released on 2010-09-05 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book originated out of a desire to provide students with an instrument which might lead them from knowledge of elementary classical and quantum physics to moderntheoreticaltechniques for the analysisof electrontransport in semiconductors. The book is basically a textbook for students of physics, material science, and electronics. Rather than a monograph on detailed advanced research in a speci?c area, it intends to introduce the reader to the fascinating ?eld of electron dynamics in semiconductors, a ?eld that, through its applications to electronics, greatly contributed to the transformationof all our lives in the second half of the twentieth century, and continues to provide surprises and new challenges. The ?eld is so extensive that it has been necessary to leave aside many subjects, while others could be dealt with only in terms of their basic principles. The book is divided into ?ve major parts. Part I moves from a survey of the fundamentals of classical and quantum physics to a brief review of basic semiconductor physics. Its purpose is to establish a common platform of language and symbols, and to make the entire treatment, as far as pos- ble, self-contained. Parts II and III, respectively, develop transport theory in bulk semiconductors in semiclassical and quantum frames. Part IV is devoted to semiconductor structures, including devices and mesoscopic coherent s- tems. Finally, Part V develops the basic theoretical tools of transport theory within the modern nonequilibrium Green-function formulation, starting from an introduction to second-quantization formalism.
Download or read book Electron Transport in Nanosystems written by Janez Bonca and published by Springer Science & Business Media. This book was released on 2008-10-24 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the NATO Advanced Research Workshop on Electron Transport in Nanosystems Yalta, Ukraine 17-21 September 2007
Download or read book Non equilibrium Many body States in Carbon Nanotube Quantum Dots written by Tokuro Hata and published by Springer. This book was released on 2019-05-14 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the first experiment revealing several unexplored non-equilibrium properties of quantum many-body states, and addresses the interplay between the Kondo effect and superconductivity by probing shot noise. In addition, it describes in detail nano-fabrication techniques for carbon nanotube quantum dots, and a measurement protocol and principle that probes both equilibrium and non-equilibrium quantum states of electrons. The book offers various reviews of topics in mesoscopic systems: shot noise measurement, carbon nanotube quantum dots, the Kondo effect in quantum dots, and quantum dots with superconducting leads, which are relevant to probing non-equilibrium physics. These reviews offer particularly valuable resources for readers interested in non-equilibrium physics in mesoscopic systems. Further, the cutting-edge experimental results presented will allow reader to catch up on a vital new trend in the field.
Download or read book Electron Transport in Quantum Dots written by Jonathan P. Bird and published by . This book was released on 2014-09-01 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonequilibrium Quantum Transport Physics In Nanosystems Foundation Of Computational Nonequilibrium Physics In Nanoscience And Nanotechnology written by Felix A Buot and published by World Scientific. This book was released on 2009-08-05 with total page 838 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the first comprehensive treatment of discrete phase-space quantum mechanics and the lattice Weyl-Wigner formulation of energy band dynamics, by the originator of these theoretical techniques. The author's quantum superfield theoretical formulation of nonequilibrium quantum physics is given in real time, without the awkward use of artificial time contour employed in previous formulations. These two main quantum theoretical techniques combine to yield general (including quasiparticle-pairing dynamics) and exact quantum transport equations in phase-space, appropriate for nanodevices. The derivation of transport formulas in mesoscopic physics from the general quantum transport equations is also treated. Pioneering nanodevices are discussed in the light of the quantum-transport physics equations, and an in-depth treatment of the physics of resonant tunneling devices is given. Operator Hilbert-space methods and quantum tomography are discussed. Discrete phase-space quantum mechanics on finite fields is treated for completeness and by virtue of its relevance to quantum computing. The phenomenological treatment of evolution superoperator and measurements is given to help clarify the general quantum transport theory. Quantum computing and information theory is covered to demonstrate the foundational aspects of discrete quantum dynamics, particularly in deriving a complete set of multiparticle entangled basis states.
