Quantized Topological Magnetoelectric Effect of the Zero-plateau Quantum Anomalous Hall State PDF Download

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

View

Book Description
The topological magnetoelectric effect in a three-dimensional topological insulator is a novel phenomenon, where an electric field induces a magnetic field in the same direction, with a universal coefficient of proportionality quantized in units of $e2/2h$. Here in this paper, we propose that the topological magnetoelectric effect can be realized in the zero-plateau quantum anomalous Hall state of magnetic topological insulators or a ferromagnet-topological insulator heterostructure. The finite-size effect is also studied numerically, where the magnetoelectric coefficient is shown to converge to a quantized value when the thickness of the topological insulator film increases. We further propose a device setup to eliminate nontopological contributions from the side surface.

Author: Yoshiro Hirayama
Publisher: Springer Nature
ISBN: 9811912017
Category : Science
Languages : en
Pages : 347

View

Book Description
This book highlights recent advances in quantum control technologies with regard to hybrid quantum systems. It addresses the following topics: phonon engineering based on phononic crystals, carbon-based nano materials like graphene and nanotubes, Terahertz light technology for single-molecule and quantum dots, nuclear-spin-based metrology for semiconductor quantum systems, quantum anomalous Hall effect in magnetic topological insulators, chiral three-dimensional photonic crystals, and bio-inspired magnonic systems. Each topic, as a component in the framework of hybrid quantum systems, is concisely presented by experts at the forefront of the field. Accordingly, the book offers a valuable asset, and will help readers find advanced technologies and materials suitable for their purposes.

Author: Xiaoliang Qi
Publisher: World Scientific
ISBN: 9811231729
Category : Technology & Engineering
Languages : en
Pages : 510

View

Book Description
This book honors the remarkable science and life of Shoucheng Zhang, a condensed matter theorist known for his work on topological insulators, the quantum Hall effect, spintronics, superconductivity, and other fields. It contains the contributions displayed at the Shoucheng Zhang Memorial Workshop held on May 2-4, 2019 at Stanford University.

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

View

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: David Vanderbilt
Publisher: Cambridge University Press
ISBN: 110715765X
Category : Science
Languages : en
Pages : 395

View

Book Description
An introduction to the role of Berry phases in our modern understanding of the physics of electrons in solids.

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

View

Book Description
The search for topologically non-trivial states of matter has become an important goal for condensed matter physics. Here, we give a theoretical introduction to the quantum anomalous Hall (QAH) effect based on magnetic topological insulators in two-dimensions (2D) and three-dimensions (3D). In 2D topological insulators, magnetic order breaks the symmetry between the counter-propagating helical edge states, and as a result, the quantum spin Hall effect can evolve into the QAH effect. In 3D, magnetic order opens up a gap for the topological surface states, and chiral edge state has been predicted to exist on the magnetic domain walls. We present the phase diagram in thin films of a magnetic topological insulator and review the basic mechanism of ferromagnetic order in magnetically doped topological insulators. We also review the recent experimental observation of the QAH effect. Furthermore, we discuss more recent theoretical work on the coexistence of the helical and chiral edge states, multi-channel chiral edge states, the theory of the plateau transition, and the thickness dependence in the QAH effect.

Author: Ming-Fa Lin
Publisher: CRC Press
ISBN: 1000337413
Category : Technology & Engineering
Languages : en
Pages : 325

View

Book Description
Lithium-Ion Batteries and Solar Cells: Physical, Chemical, and Materials Properties presents a thorough investigation of diverse physical, chemical, and materials properties and special functionalities of lithium-ion batteries and solar cells. It covers theoretical simulations and high-resolution experimental measurements that promote a full understanding of the basic science to develop excellent device performance. Employs first-principles and the machine learning method to fully explore the rich and unique phenomena of cathode, anode, and electrolyte (solid and liquid states) in lithium-ion batteries Develops distinct experimental methods and techniques to enhance the performance of lithium-ion batteries and solar cells Reviews syntheses, fabrication, and measurements Discusses open issues, challenges, and potential commercial applications This book is aimed at materials scientists, chemical engineers, and electrical engineers developing enhanced batteries and solar cells for peak performance.

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

View

Book Description
After decades of searching for the dissipationless transport in the absence of any external magnetic field, quantum anomalous Hall effect (QAHE) was recently achieved in magnetic topological insulator films. However, the universal phase diagram of QAHE and its relation with quantum Hall effect (QHE) remain to be investigated. Here, we report the experimental observation of the giant longitudinal resistance peak and zero Hall conductance plateau at the coercive field in the six quintuple-layer (Cr0.12Bi0.26Sb0.62)2Te3 film, and demonstrate the metal-to-insulator switching between two opposite QAHE plateau states up to 0.3 K. Moreover, the universal QAHE phase diagram is confirmed through the angle-dependent measurements. Our results address that the quantum phase transitions in both QAHE and QHE regimes are in the same universality class, yet the microscopic details are different. Additionally, the realization of the QAHE insulating state unveils new ways to explore quantum phase-related physics and applications.

Author: Lei Pan
Publisher:
ISBN:
Category :
Languages : en
Pages : 138

View

Book Description
Quantum anomalous Hall effect (QAHE) is the zero-field version of the quantum Hall effect which shows dissipationless chiral edge electron transport and quantized Hall resistance without the help of external magnetic field. In this Dissertation, we study the growth of magnetic topological insulator (MTI) Cr-doped (BiSb)2Te3 thin film, which is the host of the QAH states, using molecular beam epitaxy. We report the first observation of QAHE in a milli-meter sized device with the thin film thickness beyond the two-dimension (2D) limit. In addition, by controlling the thin film thickness down to the 2D limit, we observe a metal-to-insulator transition behavior due to the hybridization effect introduced by the vertical quantum confinement. We further investigate the temperature limiting factors of QAHE in the Cr-doped (BiSb)2Te3 system by studying the thickness and doping effects. We identify that for thin film thickness larger than 6 quintuple layers (QLs), the limiting factor is the overlap of Fermi level with the trivial bulk band. For thin film thickness equal to 6 QLs, weak ferromagnetism and pronounced superparamagnetism are the temperature limiting factors. However, modulation doping technique can significantly strengthen the ferromagnetism at this thickness. In addition, the metal-to-insulator transition behavior can also be tuned according to the doping profile of the thin film which can potentially affect the phase transition behavior in this material system. To manipulate the QAH states, we investigate the heterogenous integration of the QAH insulator or TI with antiferromagnets. We first study the QAH insulator/Cr2O3 bilayer structure and realize the QAHE on a magnetically ordered system for the first time. We identify the positive exchange bias in this structure and discover the magnetic coupling between the two material systems using polarized neutron reflectometry (PNR). We then study the undoped TI/CrSe heterostructure and realize the antiferromagnet induced magnetic proximity effect in the TI layer confirmed by both PNR and X-ray magnetic dichroism techniques. We also discover the interface-dependent proximity behavior in the heterostructure that may help our understanding towards high temperature and functional QAH states.

Author: Ruoxi Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

View

Book Description
Topological materials exhibit unique properties that make them robust against local defects and perturbations. These properties stem from the distinctive band structure compared to conventional materials, which are characterized by different topological invariants. In this thesis, we study two phenomena that arise in epitaxial topological insulator (TIs) films/heterostructures. The first phenomenon is the quantum anomalous Hall (QAH) effect. The QAH effect requires no external magnetic field and possesses non-dissipative chiral edge states that are resistant to local disorders. The second phenomenon is the topological superconducting (TSC) states. The TSC state hosts quasiparticle excitations, including Majorana zero modes (MZMs) and chiral Majorana edge modes (CMEMs). These excitations have potential applications in fault-tolerant topological quantum computations. The first experimental observation of the QAH effect was realized in molecular beam epitaxy (MBE)-grown magnetically doped TI thin films, which offer the advantages of scalability and reproducibility. However, the introduction of magnetic dopants also leads to higher disorder density in TI thin films. To overcome this limitation, we employed MBE-grown magnetically doped TI/TI/magnetically doped TI sandwich heterostructures to separate the magnetic dopants from the TI bulk. By employing this method, we successfully realized high Chern number QAH states, Chern domain walls, and hundred-nanometer-thick QAH samples. These results reveal new phases of matter and the underlying physics of the QAH phase transition induced by interlayer coupling. The second half of the thesis describes our effort in the TSC state in QAH insulators and TIs with induced superconductivity. The first project in this effort focuses on the search for CMEMs, which are predicted to emerge in QAH/superconductor hybrid structures. We examined a prior transport experiment that claimed the realization of CMEMs by measuring the two-terminal resistance. We improved the experimental design by fabricating Josephson junction and tunneling junction devices based on Bi2Te3 and (Bi,Sb)2Te3, and obtained transport results that suggest the dominance of Dirac surface states in vortex generation in the junction area.