Observation of Novel Phases of Quantum Matter Beyond Topological Insulator PDF Download

Author: Sabin Regmi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

View

Book Description
Because of the unique electronic properties, intriguing novel phenomena, and potentiality in quantum device applications, the quantum materials with non-trivial band structures have enticed a bulk of research works over the last two decades. The experimental discovery of the three-dimensional topological insulators (TIs) - bulk insulators with surface conduction via spin-polarized electrons - kicked off the flurry of research interests towards such materials, which resulted in the experimental discovery of new topological phases of matter beyond TIs. The topological semimetallic phase in Dirac, Weyl, and nodal-line semimetals is an example, where the classification depends on the dimensionality, degeneracy, and symmetry protection of the bulk band touching. The field of topology has extended to the materials that possess non-trivial topological states at/along lower-dimensional regions of the crystals as well. A class of such materials is the higher-order topological insulator in which both bulk and surface are insulating, but symmetry-protected conducting channels can appear along the hinges or corners of the crystal. Recently, significant focus has been given to the study of the interplay among various physical parameters such as topology, geometry, magnetism, and electronic correlation. Kagome systems have emerged as fertile ground to study the interaction among such parameters in a material class. Charge density wave (CDW) order in quantum materials remains an important topic of study given its co-existence or competence with superconductivity and magnetic ordering. In this dissertation, we study the electronic structure of quantum material systems beyond TIs, particularly the lanthanide element-based and correlated systems, by utilizing state-of-art angle-resolved photoemission spectroscopy with collaborative support from first-principles calculations and transport and magnetic measurements. The lanthanide-based materials are interesting because of the possible magnetic ordering and electron correlations that the lanthanide 4f electrons may bring into the table. Our work on the Europium-based antiferromagnetic material EuIn2As2 highlights this material as a promising ground to study the interplay of different kinds of topological orders including higher-order topology with magnetism. Temperature-dependent measurements reveal a band splitting near the Fermi level below the antiferromagnetic transition. Another study on the samarium- and neodymium-based materials SmSbTe and NdSbTe shows the presence of multiple nodal lines that remain gapless even in the presence of spin-orbit coupling. We also studied a van der Waals kagome semiconductor Nb3I8, where we observed flat and weakly dispersing bands in its electronic structure. These bands are observed to be sensitive to light polarization and originate from the breathing kagome plane of niobium atoms. Next, our study in Gadolinium-based van der Waals material GdTe3 shows the presence of a momentum-dependent CDW gap and the presence of antiferromagnetic ordering that could prove important to study the interaction of CDW and magnetic orders in this material. Overall, the works under this dissertation reveal the electronic properties in correlated systems that range from insulator to metals/semimetals and from topological insulator to topological semimetals, kagome semiconductor, and CDW material.

Author: Joseph C. Szabo
Publisher:
ISBN:
Category : Condensed matter
Languages : en
Pages : 0

View

Book Description
Understanding and identifying quantum phases have been longstanding pursuits in the field condensed matter physics. The most exciting modern problems lie at the intersection of strong correlations and quantum information where highly entangled phases of matter are the most difficult to solve both analytically and computationally. The overarching aim of this thesis is to advance our understanding of strongly correlated materials in light of advanced, microscopic measurement techniques, capable of imaging and manipulating single qubits and measuring fascinating physics such as quantum entanglement. We begin our study with the Fermi-Hubbard model, a theoretical model that captures the insulating and conducting phases of high-temperature superconducting materials, and we end our discussion by characterizing novel quantum phases and dynamics realized on cutting-edge quantum simulation platforms. Our first focus is on the repulsive Fermi-Hubbard model. We elucidate the mechanism by which a Mott insulator transforms into a non-Fermi liquid metal upon increasing disorder at half filling. By correlating maps of the local density of states, the local magnetization, and the local bond conductivity, we find a collapse of the Mott gap toward a V-shape pseudogapped density of states that occurs concomitantly with the decrease of magnetism around the highly disordered sites, while the electronic bond conductivity increases. We propose that these metallic regions percolate to form an emergent non-Fermi liquid phase with a conductivity that increases with temperature. Our results provide one of the first microscopic investigations of dynamical response and how these two phases (correlated metal and Mott insulator) coexist microscopically and lead to an overall macroscopic phase transition. Our work provides novel predictions for electron conductivity measured via local microwave impedance combined with charge and spin local spectroscopies. Expanding beyond the ground state properties of interacting matter, revolutionary quantum simulation experiments provide access to new regimes of quantum matter such as dynamical transitions and steady states in nonequilibrium conditions. This allows us to explore the most mind-boggling properties of interacting quantum systems: entanglement. In our first venture exploring the field of nonequilibrium quantum dynamics, we bridge foundational atomic, molecular, and optical (AMO) and condensed matter models. We investigate competing entanglement dynamics in an Ising-spin chain coupled to an external central ancilla qudit. In studying the real-time behavior following a quench from an unentangled spin-ancilla state, we find that the ancilla entanglement entropy tracks the dynamical phase transition in the underlying spin system. In this composite setting, purely spin-spin entanglement metrics such as mutual information and quantum Fisher information (QFI) decay as the ancilla entanglement entropy grows. We define multipartite entanglement loss (MEL) as the difference between collective magnetic fluctuations and QFI, which is zero in the pure spin chain limit. MEL directly quantifies the ancilla's effect on the development of spin-spin entanglement. One of our central results is that we find MEL is proportional to the exponential of entanglement entropy in real-time. Our results provide a platform for exploring composite system entanglement dynamics and suggest that MEL serves as a quantitative estimate of information entropy shared between collective spins and the ancilla qudit. Our results present a new framework that connects physical spin-fluctuations, QFI, and bipartite entanglement entropy between collective quantum systems. We reduce the qudit/bosonic environment to a single (central) qubit as to investigate the scrambling capacity added by a simple c-qubit. We present the novel ring-star Ising model as a bridge between fast-slow scrambling: a locally interacting spin-1/2 system uniformly coupled to a central qubit vertex. Each spin becomes next-nearest neighbor to all others through the c-qubit, where stronger central coupling continuously degrades any sense of locality and achieves effective all-to-all interactions. Meanwhile, the central qubit adds two level structure to all previous eigenstates in the spectrum. We study operator and entanglement dynamics in a nonintegrable ring-star, spin-1/2 Ising model with tunable central spin coupling. As the interaction with the c-spin increases across all sites, we find a surprising transition from super-ballistic scrambling and information growth to continuously restricted sub-ballistic entanglement and increasingly inhibited operator growth. This slow growth occurs on intermediate timescales that extend exponentially with increasing coupling, indicative of logarithmic entanglement growth. We provide exact dynamics of small systems working with non-equilibrium, effective infinite temperature states, and additionally contribute analytic early-time expansions that support the observed rapid scrambling to quantum Zeno-like crossover. Finally, we apply the properties of entanglement to highlight numerically approximate methods for simulating quantum and semiclassical systems. When entanglement slowly develops locally, tensor network methods allow for efficient simulation of the minimal Hilbert space required to store the quantum wavefunction evolving under Schrodinger dynamics or quantum operators under Heisenberg evolution. In the limit of long-range interactions, the system is increasingly semiclassical where the wavefunction spreads rapidly, but the full quantum Hilbert space approaches proximate conservation of collective observables. Here we review tensor network and semiclassical numerical algorithms and provide a brief discussion on applying them to simulate the quench dynamics of the Heisenberg model. We highlight the regimes where we expect them to be accurate and the intermediate regions where the two become approximate from different limits on the range of interaction.

Author: Michael I. Monastyrsky
Publisher: Springer Science & Business Media
ISBN: 3540312641
Category : Science
Languages : en
Pages : 263

View

Book Description
This book reports new results in condensed matter physics for which topological methods and ideas are important. It considers, on the one hand, recently discovered systems such as carbon nanocrystals and, on the other hand, new topological methods used to describe more traditional systems such as the Fermi surfaces of normal metals, liquid crystals and quasicrystals. The authors of the book are renowned specialists in their fields and present the results of ongoing research, some of it obtained only very recently and not yet published in monograph form.

Author: Saurabh Basu
Publisher: Springer Nature
ISBN: 9819953219
Category : Science
Languages : en
Pages : 226

View

Book Description
The book is mainly designed for post-graduate students to learn modern-day condensed matter physics. While emphasizing an experiment called the ‘Quantum Hall effect’, it introduces the subject of 'Topology' and how the topological invariants are related to the quantization of the Hall plateaus. Thus, the content tries to deliver an account of the topological aspects of materials that have shaped the study of condensed matter physics in recent times. The subject is often quite involved for a student to grasp the fundamentals and relate them to physical phenomena. Further, these topics are mostly left out of the undergraduate curriculum, although they often require a simplistic view of the concepts involved to be presented pedagogically. The book contains examples, worked-out concepts, important derivations, diagrams for illustration, etc. to aid the understanding of the students. The book also emphasizes the experimental discoveries that put the subject in its perspective and elaborate on the applications which are likely to be of interest to scientists and engineers.

Author: Bei Zeng
Publisher: Springer
ISBN: 1493990845
Category : Computers
Languages : en
Pages : 364

View

Book Description
This book approaches condensed matter physics from the perspective of quantum information science, focusing on systems with strong interaction and unconventional order for which the usual condensed matter methods like the Landau paradigm or the free fermion framework break down. Concepts and tools in quantum information science such as entanglement, quantum circuits, and the tensor network representation prove to be highly useful in studying such systems. The goal of this book is to introduce these techniques and show how they lead to a new systematic way of characterizing and classifying quantum phases in condensed matter systems. The first part of the book introduces some basic concepts in quantum information theory which are then used to study the central topic explained in Part II: local Hamiltonians and their ground states. Part III focuses on one of the major new phenomena in strongly interacting systems, the topological order, and shows how it can essentially be defined and characterized in terms of entanglement. Part IV shows that the key entanglement structure of topological states can be captured using the tensor network representation, which provides a powerful tool in the classification of quantum phases. Finally, Part V discusses the exciting prospect at the intersection of quantum information and condensed matter physics – the unification of information and matter. Intended for graduate students and researchers in condensed matter physics, quantum information science and related fields, the book is self-contained and no prior knowledge of these topics is assumed.

Author: János K. Asbóth
Publisher: Springer
ISBN: 3319256076
Category : Science
Languages : en
Pages : 176

View

Book Description
This course-based primer provides newcomers to the field with a concise introduction to some of the core topics in the emerging field of topological insulators. The aim is to provide a basic understanding of edge states, bulk topological invariants, and of the bulk--boundary correspondence with as simple mathematical tools as possible. The present approach uses noninteracting lattice models of topological insulators, building gradually on these to arrive from the simplest one-dimensional case (the Su-Schrieffer-Heeger model for polyacetylene) to two-dimensional time-reversal invariant topological insulators (the Bernevig-Hughes-Zhang model for HgTe). In each case the discussion of simple toy models is followed by the formulation of the general arguments regarding topological insulators. The only prerequisite for the reader is a working knowledge in quantum mechanics, the relevant solid state physics background is provided as part of this self-contained text, which is complemented by end-of-chapter problems.

Author: Sanju Gupta
Publisher:
ISBN: 9783319765976
Category : Materials science
Languages : en
Pages : 297

View

Book Description
This book presents the most important advances in the class of topological materials and discusses the topological characterization, modeling and metrology of materials. Further, it addresses currently emerging characterization techniques such as optical and acoustic, vibrational spectroscopy (Brillouin, infrared, Raman), electronic, magnetic, fluorescence correlation imaging, laser lithography, small angle X-ray and neutron scattering and other techniques, including site-selective nanoprobes. The book analyzes the topological aspects to identify and quantify these effects in terms of topology metrics. The topological materials are ubiquitous and range from (i) de novo nanoscale allotropes of carbons in various forms such as nanotubes, nanorings, nanohorns, nanowalls, peapods, graphene, etc. to (ii) metallo-organic frameworks, (iii) helical gold nanotubes, (iv) Möbius conjugated polymers, (v) block co-polymers, (vi) supramolecular assemblies, to (vii) a variety of biological and soft-matter systems, e.g. foams and cellular materials, vesicles of different shapes and genera, biomimetic membranes, and filaments, (viii) topological insulators and topological superconductors, (ix) a variety of Dirac materials including Dirac and Weyl semimetals, as well as (x) knots and network structures. Topological databases and algorithms to model such materials have been also established in this book. In order to understand and properly characterize these important emergent materials, it is necessary to go far beyond the traditional paradigm of microscopic structure-property-function relationships to a paradigm that explicitly incorporates topological aspects from the outset to characterize and/or predict the physical properties and currently untapped functionalities of these advanced materials. Simulation and modeling tools including quantum chemistry, molecular dynamics, 3D visualization and tomography are also indispensable. These concepts have found applications in condensed matter physics, materials science and engineering, physical chemistry and biophysics, and the various topics covered in the book have potential applications in connection with novel synthesis techniques, sensing and catalysis. As such, the book offers a unique resource for graduate students and researchers alike.

Author: Xinyu Liu
Publisher: Woodhead Publishing
ISBN: 0081027362
Category : Technology & Engineering
Languages : en
Pages : 398

View

Book Description
Chalcogenide: From 3D to 2D and Beyond reviews graphene-like 2D chalcogenide systems that include topological insulators, interesting thermoelectric structures, and structures that exhibit a host of spin phenomena that are unique to 2D and lower-dimensional geometries. The book describes state-of-the-art materials in growth and fabrication, magnetic, electronic and optical characterization, as well as the experimental and theoretical aspects of this family of materials. Bulk chalcogenides, chalcogenide films, their heterostructures and low-dimensional chalcogenide-based quantum structures are discussed. Particular attention is paid to findings that are relevant to the continued search for new physical phenomena and new functionalities. Finally, the book covers the enormous opportunities that have emerged as it has become possible to achieve lower-dimensional chalcogenide structures by epitaxial techniques. Provides readers with foundational information on the materials growth, fabrication, magnetic, electronic and optical characterization of chalcogenide materials Discusses not only bulk chalcogenides and chalcogenide thin films, but also two-dimensional chalcogenide materials systems Reviews the most important applications in optoelectronics, photovoltaics and thermoelectrics

Author: Henrik Bruus
Publisher: Oxford University Press
ISBN: 0198566336
Category : Science
Languages : en
Pages : 458

View

Book Description
The book is an introduction to quantum field theory applied to condensed matter physics. The topics cover modern applications in electron systems and electronic properties of mesoscopic systems and nanosystems. The textbook is developed for a graduate or advanced undergraduate course with exercises which aim at giving students the ability to confront real problems.

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

View

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.