Exploiting Topological Insulators for Majorana Devices and Physics Via Molecular Beam Epitaxy PDF Download

Author: Peter Schüffelgen
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Huixia Luo
Publisher: John Wiley & Sons
ISBN: 1119407338
Category : Technology & Engineering
Languages : en
Pages : 416

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Book Description
This book is the first pedagogical synthesis of the field of topological insulators and superconductors, one of the most exciting areas of research in condensed matter physics. Presenting the latest developments, while providing all the calculations necessary for a self-contained and complete description of the discipline, it is ideal for researchers and graduate students preparing to work in this area, and it will be an essential reference both within and outside the classroom. The book begins with the fundamental description on the topological phases of matter such as one, two- and three-dimensional topological insulators, and methods and tools for topological material's investigations, topological insulators for advanced optoelectronic devices, topological superconductors, saturable absorber and in plasmonic devices. Advanced Topological Insulators provides researchers and graduate students with the physical understanding and mathematical tools needed to embark on research in this rapidly evolving field.

Author: Frank Ortmann
Publisher: John Wiley & Sons
ISBN: 3527337024
Category : Technology & Engineering
Languages : en
Pages : 434

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Book Description
There are only few discoveries and new technologies in physical sciences that have the potential to dramatically alter and revolutionize our electronic world. Topological insulators are one of them. The present book for the first time provides a full overview and in-depth knowledge about this hot topic in materials science and condensed matter physics. Techniques such as angle-resolved photoemission spectrometry (ARPES), advanced solid-state Nuclear Magnetic Resonance (NMR) or scanning-tunnel microscopy (STM) together with key principles of topological insulators such as spin-locked electronic states, the Dirac point, quantum Hall effects and Majorana fermions are illuminated in individual chapters and are described in a clear and logical form. Written by an international team of experts, many of them directly involved in the very first discovery of topological insulators, the book provides the readers with the knowledge they need to understand the electronic behavior of these unique materials. Being more than a reference work, this book is essential for newcomers and advanced researchers working in the field of topological insulators.

Author: Shuang Li
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Searching for energy dissipation-less systems has become increasingly important for low power electronic devices. Topological insulators, a new topological state of quantum matter, have recently been proposed as an emerging material for use in low power electronics, because of the unique transport along its topologically protected edge/surface states. In addition, it has been predicted that the incorporation of magnetic elements into topological insulators could lead to the quantum anomalous Hall state, which is a truly dissipation-less system. However, the material quality of topological insulator thin films remains as a major stumbling block for exploring the novel physics of topological insulators and their proposed applications. In the first part of this thesis, I will first describe an advanced thin film deposition technique, molecular beam epitaxy (MBE) and the mini-MBE system we designed and built for topological insulator thin film growth. Then I will briefly illustrate some basic principles and sample preparation methods for a variety of characterization techniques we used for the material property investigation. In the second part of this thesis, I will present the growth and characterization of topological insulator bismuth telluride thin films grown by a two-step MBE process developed as part of this research. By optimizing the growth recipe and particularly developing the two-step growth method, defect densities were significantly reduced and higher crystal and surface quality bismuth telluride thin films were achieved. The existence of a topological surface state on our bismuth telluride thin films was also confirmed. The Fermi level of our bismuth telluride thin film was tuned to very close to the bulk gap region. The successful growth of centimeter-sized, uniform, high quality topological insulator thin films provides an excellent platform for both fundamental studies of the properties of topological insulators and fabrications of mesoscopic devices. Finally, I will report on the first successful growth of gadolinium substituted bismuth telluride thin films with high Gd concentrations by MBE. We systematically investigated the crystal structure, band structure, magnetic, and electronic properties of gadolinium substituted bismuth telluride thin films. The topological surface state was found to remain intact by Gd substitution into bismuth telluride. Although ferromagnetic behavior in gadolinium substituted bismuth telluride thin films was not observed above 2K by both magnetic and magneto-transport measurements, gadolinium substituted bismuth telluride thin films were found to have a Curie susceptibility due to the paramagnetic Gd ions with an atomic magnetic moment of 6.93 Bohr magneton per Gd ion, which suggests that it is possible to realize dissipation-less transport with a small external magnetic field or with a ferromagnetic layer on top of gadolinium substituted bismuth telluride thin films.

Author: Ke He
Publisher: Elsevier Inc. Chapters
ISBN: 0128086904
Category : Science
Languages : en
Pages : 36

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Book Description
Material is a key to the experimental observation of novel quantum phenomena predicted in topological insulators. In this chapter, we review the recent theoretic and experimental efforts devoted to improving the existing topological insulator materials and exploring new topological insulators. The emphasis is on growth and engineering of the properties of topological insulator thin films by molecular beam epitaxy for realization of various quantum effects.

Author:
Publisher: Academic Press
ISBN: 0323915108
Category : Science
Languages : en
Pages : 240

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Book Description
Topological Insulator and Related Topics, Volume 108 in the Semiconductors and Semimental series, highlights new advances in the field, with this new volume presenting interesting chapters on topics such as Majorana modes at the ends of one dimensional topological superconductors, Optical/electronic properties of Weyl semimetals, High magnetic fields to unveil the electronic structure, magnetic field-induced transitions, and unconventional transport properties of topological semimetals, New aspects of strongly correlated superconductivity in the nearly flat-band regime, Anomalous transport properties in topological semimetals, Pseudo-gauge field and piezo-electromagnetic response in topological materials, Topological Gapped States Protected by Spatial Symmetries, and more. - Provides the authority and expertise of leading contributors from an international board of authors - Presents the latest release in the Semiconductors and Semimetals series - Updated release includes the latest information on Topological Insulator and Related Topics

Author: Naoto Nagaosa
Publisher: Elsevier Inc. Chapters
ISBN: 0128086912
Category : Science
Languages : en
Pages : 39

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Book Description
The discovery of the rich topological structures of electronic states in solids has opened up many interesting possibilities. The “twist” of the wavefunctions in momentum space, which is characterized by topological invariants, leads to the robust edge or surface states. The electron fractionalization associated with these topological states brings about the novel physics such as absence of localization, topological magneto-electric effect, and Majorana fermions. Here we describe the principles and some concrete examples of the theoretical design of the topological materials and their functions based on these recent developments.

Author:
Publisher: Elsevier
ISBN: 0444633189
Category : Science
Languages : en
Pages : 349

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Book Description
Topological Insulators, volume six in the Contemporary Concepts of Condensed Matter Series, describes the recent revolution in condensed matter physics that occurred in our understanding of crystalline solids. The book chronicles the work done worldwide that led to these discoveries and provides the reader with a comprehensive overview of the field. Starting in 2004, theorists began to explore the effect of topology on the physics of band insulators, a field previously considered well understood. However, the inclusion of topology brings key new elements into this old field. Whereas it was thought that all band insulators are essentially equivalent, the new theory predicts two distinct classes of band insulators in two spatial dimensions and 16 classes in three dimensions. These "topological" insulators exhibit a host of unusual physical properties, including topologically protected gapless surface states and exotic electromagnetic response, previously thought impossible in such systems. Within a short time, this new state of quantum matter, topological insulators, has been discovered experimentally both in 2D thin film structures and in 3D crystals and alloys. It appears that topological insulators are quite common in nature, and there are dozens of confirmed substances that exhibit this behavior. Theoretical and experimental studies of these materials are ongoing with the goal of attaining the fundamental understanding and exploiting them in future practical applications. - Usable as a textbook for graduate students and as a reference resource for professionals - Includes the most recent discoveries and visions for future technological applications - All authors are prominent in the field

Author: Peng Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 132

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Topological insulator (TI) is a new class of quantum material with inverted band structure caused by strong spin-orbit coupling (SOC), resulting an insulating bulk and topologically protected surface states. By introducing magnetism to break the time-reversal symmetry, it can host emerging topological quantum phases such as quantum anomalous Hall (QAH) effect, axion insulator quantum phase, and can host chiral Majorana fermion when coupled to superconductors. The goal of this dissertation is to study these quantum phases by material growth and transport measurements. First, we studied the growth condition by molecular beam epitaxy (MBE) and achieved high quality magnetically doped topological insulator (MTI) film growth that can host QAH effect. To understand the different origins of zero Hall conductance plateau in QAH insulators and axion insulators, we carried out the thickness dependent study on MTI sandwiched structures and observed a dimension crossover between 2D QAH and 3D axion insulators by minor loops measurements and scaling analysis. Then, we investigated the QAH insulator and antiferromagnetic heterostructures which offer an additional degree of freedom to manipulate the QAH state in MTI. By proximity coupling the QAH insulator to antiferromagnetic insulator Al-Cr2O3, we observed an exchange biased QAH effect, and the exchange bias can be effectively controlled by a field training process. In addition, chiral Majorana edge modes are reported to exist in QAH insulator and superconductors heterostructures. Aiming to understand the discrepancy of recent experimental reports, we fabricated QAH insulator with superconductor and normal metals hybrid devices, and we found the details of material characteristics, interface conditions play important roles on the experiment observations. Finally, two collaborative works closely related to the main scope of this dissertation are introduced. To probe the size limit and to understand the inter-channel scattering of QAH effect, we fabricated mesoscopic scale sub-micron size QAH insulator devices and carried out size dependent studies. Enabled by the successful growth of QAH film on insulating 2D van-der-Waals substrate MICA, we were able to fabricate dual-gate QAH device by exfoliation and transfer techniques. By applying a vertical electric field, we observe a topological phase transition from QAH to a trivial insulator state. This research will greatly improve the understanding of emerging topological quantum physics, and lead to the new revolution of quantum electronic devices.

Author: Li Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Topological insulators are a special category of materials that are insulating in the bulk but have robust conducting surface states. As an ideal candidate for low power electronics, spintronic and quantum computation, topological insulators have been actively studied both theoretically and experimentally in the past couple of years. To achieve high quality thin films of topological insulators and understand their properties thoroughly is a critical step towards all potential applications. In this dissertation, I will introduce methods to fabricate high quality topological insulator Bi2Se3 thin films using both pulsed laser deposition (PLD) and molecular beam epitaxy (MBE) with a radio frequency (RF) cracker cell. Using PLD, bilayers of topological insulator Bi2Se3 and insulating ferromagnet EuS were fabricated. Weak localization of the surface states was observed at the interface under the Curie temperature of EuS, as a direct evidence of the proximity effect. Using MBE with the RF cracker cell, high quality ultrathin Bi2Se3 films were successfully grown. Analysis of the magneto-resistance of those ultrathin samples measured at low temperature shows both the characteristic weak antilocalization from the surface states and the weak localization from the quantized bulk states, in good agreement with theoretical predictions. With our abilities to add various dopants during the deposition, and to deposit high quality thin films of different materials other than topological insulators, in both the MBE and PLD systems, we are excited to see the door to more interesting structures and fascinating physics opening in front of us.