LDRD Final Report on Bloch Oscillations in Two-dimensional Nanostructure Arrays for High Frequency Applications PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 42
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Book Description
We have investigated the physics of Bloch oscillations (BO) of electrons, engineered in high mobility quantum wells patterned into lateral periodic arrays of nanostructures, i.e. two-dimensional (2D) quantum dot superlattices (QDSLs). A BO occurs when an electron moves out of the Brillouin zone (BZ) in response to a DC electric field, passing back into the BZ on the opposite side. This results in quantum oscillations of the electron--i.e., a high frequency AC current in response to a DC voltage. Thus, engineering a BO will yield continuously electrically tunable high-frequency sources (and detectors) for sensor applications, and be a physics tour-de-force. More than a decade ago, Bloch oscillation (BO) was observed in a quantum well superlattice (QWSL) in short-pulse optical experiments. However, its potential as electrically biased high frequency source and detector so far has not been realized. This is partially due to fast damping of BO in QWSLs. In this project, we have investigated the possibility of improving the stability of BO by fabricating lateral superlattices of periodic coupled nanostructures, such as metal grid, quantum (anti)dots arrays, in high quality GaAs/Al(subscript x)Ga{sub 1-x}As heterostructures. In these nanostructures, the lateral quantum confinement has been shown theoretically to suppress the optical-phonon scattering, believed to be the main mechanism for fast damping of BO in QWSLs. Over the last three years, we have made great progress toward demonstrating Bloch oscillations in QDSLs. In the first two years of this project, we studied the negative differential conductance and the Bloch radiation induced edge-magnetoplasmon resonance. Recently, in collaboration with Prof. Kono's group at Rice University, we investigated the time-domain THz magneto-spectroscopy measurements in QDSLs and two-dimensional electron systems. A surprising DC electrical field induced THz phase flip was observed. More measurements are planned to investigate this phenomenon. In addition to their potential device applications, periodic arrays of nanostructures have also exhibited interesting quantum phenomena, such as a possible transition from a quantum Hall ferromagnetic state to a quantum Hall spin glass state. It is our belief that this project has generated and will continue to make important impacts in basic science as well as in novel solid-state, high frequency electronic device applications.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 42
Get Book Here
Book Description
We have investigated the physics of Bloch oscillations (BO) of electrons, engineered in high mobility quantum wells patterned into lateral periodic arrays of nanostructures, i.e. two-dimensional (2D) quantum dot superlattices (QDSLs). A BO occurs when an electron moves out of the Brillouin zone (BZ) in response to a DC electric field, passing back into the BZ on the opposite side. This results in quantum oscillations of the electron--i.e., a high frequency AC current in response to a DC voltage. Thus, engineering a BO will yield continuously electrically tunable high-frequency sources (and detectors) for sensor applications, and be a physics tour-de-force. More than a decade ago, Bloch oscillation (BO) was observed in a quantum well superlattice (QWSL) in short-pulse optical experiments. However, its potential as electrically biased high frequency source and detector so far has not been realized. This is partially due to fast damping of BO in QWSLs. In this project, we have investigated the possibility of improving the stability of BO by fabricating lateral superlattices of periodic coupled nanostructures, such as metal grid, quantum (anti)dots arrays, in high quality GaAs/Al(subscript x)Ga{sub 1-x}As heterostructures. In these nanostructures, the lateral quantum confinement has been shown theoretically to suppress the optical-phonon scattering, believed to be the main mechanism for fast damping of BO in QWSLs. Over the last three years, we have made great progress toward demonstrating Bloch oscillations in QDSLs. In the first two years of this project, we studied the negative differential conductance and the Bloch radiation induced edge-magnetoplasmon resonance. Recently, in collaboration with Prof. Kono's group at Rice University, we investigated the time-domain THz magneto-spectroscopy measurements in QDSLs and two-dimensional electron systems. A surprising DC electrical field induced THz phase flip was observed. More measurements are planned to investigate this phenomenon. In addition to their potential device applications, periodic arrays of nanostructures have also exhibited interesting quantum phenomena, such as a possible transition from a quantum Hall ferromagnetic state to a quantum Hall spin glass state. It is our belief that this project has generated and will continue to make important impacts in basic science as well as in novel solid-state, high frequency electronic device applications.
Author: Kompa, Günter
Publisher: kassel university press GmbH
ISBN: 3862195414
Category : Compound semiconductors
Languages : en
Pages : 762
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Book Description
Trapping effects in III-V devices pose a great challenge to any microwave device modeler. Understanding their physical origins is of prime importance to create physics-related reliable device models. The treatment of trapping phenomena is commonly beyond the classical higher-education level of communication engineers. This book provides any basic material needed to understand trapping effects occurring primarily in GaAs and GaN power HEMT devices. As the text material covers interdisciplinary topics such as crystal defects and localized charges, trap centers and trap dynamics, deep-level transient spectroscopy, and trap centers in passivation layers, the book will be of interest to graduate students of electrical engineering, communication engineering, and physics as well as materials, device, and circuit engineers in research and industry.
Author: Daniel Esteve
Publisher: Elsevier
ISBN: 9780444517289
Category : Computers
Languages : en
Pages : 644
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Book Description
Presents the lecture notes of the Les Houches Summer School on Quantum entanglement and information processing. This book aims to establish connections between the communities of quantum optics and of quantum electronic devices working in the area of quantum computing. It is useful for graduate students with a basic knowledge of quantum mechanics.
Author: Chi-chung Francis Ling
Publisher: World Scientific
ISBN: 9811203180
Category : Science
Languages : en
Pages : 338
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Book Description
The research of functional materials has attracted extensive attention in recent years, and its advancement nitrifies the developments of modern sciences and technologies like green sciences and energy, aerospace, medical and health, telecommunications, and information technology. The present book aims to summarize the research activities carried out in recent years devoting to the understanding of the physics and chemistry of how the defects play a role in the electrical, optical and magnetic properties and the applications of the different functional materials in the fields of magnetism, optoelectronic, and photovoltaic etc.
Author: Tapan Chatterji
Publisher: Springer Science & Business Media
ISBN: 9781402018442
Category : Science
Languages : en
Pages : 468
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Book Description
This book is a comprehensive account of the present understanding of an important class of perovskite oxide materials with potential industrial applications. The chapters are written by well-known scientists who are on the forefront of the field and have directly contributed to its recent progress. Special care has been taken to maintain a balance between the space devoted to new experimental results and that devoted to recent theoretical developments. The book contains recent experimental and theoretical results on colossal magnetoresistive (CMR) manganites not covered by any other book in the field, and hence this will be very beneficial to graduate students and researchers in condensed matter and applied physics, materials science and solid state chemistry.
Author: Mangal Roy
Publisher: Elsevier Inc. Chapters
ISBN: 0128071036
Category : Science
Languages : en
Pages : 19
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Book Description
In joint replacement surgery with suboptimal bone, allograft materials are often used to achieve biological fixation of the metallic implant to the host bone and reducing the implant fixation time. The most commonly used techniques are cemented and hydroxyapatite (HA)-coated metallic implants. Typically, HA coatings are suggested for patients with better bone stock, whereas recommended implant fixation process for most other osteoporotic patients is bone cements. In general, there is a long-standing need to improve the performance of hip and other devices for longer in vivo implant lifetime that can help in reducing the number of revision surgeries, as well as minimizing physical and mental trauma to the patient. To achieve these goals, it is important to understand the mechanical and biological properties of coatings that can influence not only its short- and long-term bioactivity but also life span in vivo. Over the years, it has been recognized that the stability of a coated implant is governed by its physical and mechanical properties. A coating that separates from the implant provides no advantage over an uncoated implant and undesirable due to problems with debris materials, which can lead to osteolysis. Therefore, it is important to properly characterize the coated implants in terms of its physical and mechanical properties. In this chapter, specific details on coating characterization techniques including sample dimensions, sample preparation, experimental procedure and data interpretation are discussed. In particular, the standards and requirements of regulatory organizations are presented elucidating the significance and use of each characterization. It is important to appreciate that mechanical properties of coatings can only be determined with certain coating specification such as coating thickness. This chapter is designed even for non-experts to follow mechanical property characterizations of coatings on medical implants.
Author: Gerard Mourou
Publisher:
ISBN: 9811217130
Category : Electronic books
Languages : en
Pages : 269
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Book Description
Author: Benoît Deveaud
Publisher: IOS Press
ISBN: 9781586033521
Category : Science
Languages : en
Pages : 584
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Book Description
The purpose of this course was to give an overview of the physics of artificial semiconductor structures confining electrons and photons. It furnishes the background for several applications in particular in the domain of optical devices, lasers, light emitting diodes or photonic crystals. The effects related to the microactivity polaritons, which are mixed electromagnetic radiation-exciton states inside a semiconconductor microactivity are covered. The study of the characteristics of such states shows strong relations with the domain of cavity quantum electrodynamics and thus with the investigation of some fundamental theoretical concepts.
Author: Masataka Higashiwaki
Publisher: Springer Nature
ISBN: 3030371530
Category : Technology & Engineering
Languages : en
Pages : 768
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Book Description
This book provides comprehensive coverage of the new wide-bandgap semiconductor gallium oxide (Ga2O3). Ga2O3 has been attracting much attention due to its excellent materials properties. It features an extremely large bandgap of greater than 4.5 eV and availability of large-size, high-quality native substrates produced from melt-grown bulk single crystals. Ga2O3 is thus a rising star among ultra-wide-bandgap semiconductors and represents a key emerging research field for the worldwide semiconductor community. Expert chapters cover physical properties, synthesis, and state-of-the-art applications, including materials properties, growth techniques of melt-grown bulk single crystals and epitaxial thin films, and many types of devices. The book is an essential resource for academic and industry readers who have an interest in, or plan to start, a new R&D project related to Ga2O3.
Author: Hans Volland
Publisher: CRC Press
ISBN: 1351364189
Category : Science
Languages : en
Pages : 769
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Book Description
The participation of such diverse scientific and technical disciplines as meteorology, astronomy, atmospheric electricity, ionospheric and magnetospheric physics, electromagnetic wave propagation, and radio techniques in the research of atmospherics means that results are published in scientific papers widely spread throughout the literature. This Handbook collects the latest knowledge on atmospherics and presents it in two volumes. Each chapter is written by an expert in his or her field. Topics include the physics of thunderclouds, thunder, global atmospheric electric currents, biological aspects of sferics, and various space techniques for detecting lightning within our own atmosphere as well as in the atmospheres of other planets. Up-to-date applications and methodology are detailed. Volumes I and II offer a comprehensive discussion that together will serve as an important resource for practitioners, professionals, and students alike.
