Angle Resolved Photoemission Spectroscopy of Delafossite Metals


Book Description

This thesis describes the results of angle resolved photoemission spectroscopy experiments on delafossite oxide metals, and theoretical work explaining these observations. The study was motivated by the extraordinarily high conductivity of the non-magnetic delafossites PdCoO2 and PtCoO2, the measurement of whose electronic structure is reported and discussed. Two unexpected effects were observed in the course of the investigation; each is described and analysed in detail. Firstly, a previously unrecognised type of spectroscopic signal, allowing the non-magnetic probe of photoemission to become sensitive to spin-spin correlations, was observed in the antiferromagnetic PdCrO2. Its origin was identified as the Kondo-like coupling of itinerant and Mott insulating electrons. Furthermore, surface states exhibiting an unusually large Rashba-like spin-splitting were observed on the transition metal terminated surfaces of delafossites. The large inversion symmetry breaking energy scale, a consequence of the unusual structure of the surface layer, is identified as the origin of the effect.




Probing Unconventional Transport Regimes in Delafossite Metals


Book Description

This thesis describes in-depth studies of the remarkable electronic transport within the ultrahigh conductivity delafossite metals PtCoO_2 and PdCoO_2 using the tool of focused ion beam (FIB) microstucturing. Despite being first synthesised over 50 years ago, important questions remain regarding both the origin of the unusually high conductivity of these compounds and the consequences of their unique properties for unconventional electronic transport, such as that within the ballistic regime. The thesis explores both these areas. High-energy electron irradiation is used to examine the effects of deliberately introducing point defects into PdCoO_2 and PtCoO_2, demonstrating that the extremely low resistivity of these materials stems from an extreme purity as high as 1 defect in 120,000 atoms, rather than a novel scattering suppression mechanism. In addition, studies of the electronic transport in micron-scale squares of these metals show that their broadly hexagonal Fermi surfaces lead not only to long range ballistic behaviour but novel ballistic regime phenomena which cannot be observed in materials with a higher-symmetry Fermi surface.




Manipulating Anisotropic Transport and Superconductivity by Focused Ion Beam Microstructuring


Book Description

This thesis presents pioneering work in the relatively new field of focused ion beam (FIB) sculpting of single crystals to produce bespoke devices and enable the investigation of physics that cannot be studied in bulk samples. It begins with a comprehensive and didactic account of how to achieve this sculpting, revealing the ‘tricks of the trade’ of state-of-the-art FIB microstructuring. In subsequent chapters, the author presents ground-breaking results obtained from microstructures of the delafossite oxide metal PdCoO2 and the heavy fermion superconductor CeIrIn5. In these elegant, forefront experiments, a new form of directional ballistic transport in the ultra-pure delafossites is described and explained. Furthermore, a new way to spatially modulate superconductivity induced by strain is demonstrated with electrical transport measurements that agree well with predictions based on thermoelastic finite element simulations.




Multifunctional Oxide Heterostructures


Book Description

This book is devoted to the rapidly developing field of oxide thin-films and heterostructures. Oxide materials combined with atomic-scale precision in a heterostructure exhibit an abundance of macroscopic physical properties involving the strong coupling between the electronic, spin, and structural degrees of freedom, and the interplay between magnetism, ferroelectricity, and conductivity. Recent advances in thin-film deposition and characterization techniques made possible the experimental realization of such oxide heterostructures, promising novel functionalities and device concepts. The book consists of chapters on some of the key innovations in the field over recent years, including strongly correlated oxide heterostructures, magnetoelectric coupling and multiferroic materials, thermoelectric phenomena, and two-dimensional electron gases at oxide interfaces. The book covers the core principles, describes experimental approaches to fabricate and characterize oxide heterostructures, demonstrates new functional properties of these materials, and provides an overview of novel applications.







Quantum Theory of Solids


Book Description

This book develops the subject from the basic principles of quantum mechanics. The emphasis is on a single statement of the ideas underlying the various approximations that have to be used and care is taken to separate sound arguments from conjecture. This book is written for the student of theoretical physics who wants to work in the field of solids and for the experimenter with a knowledge of quantum theory who is not content to take other people's arguments for granted. The treatment covers the electron theory of metals as well as the dynamics of crystals, including the author's work on the thermal conductivity of crystals which has been previously published in English.




Physics Briefs


Book Description




Oxide Electronics


Book Description

Oxide Electronics Multiple disciplines converge in this insightful exploration of complex metal oxides and their functions and properties Oxide Electronics delivers a broad and comprehensive exploration of complex metal oxides designed to meet the multidisciplinary needs of electrical and electronic engineers, physicists, and material scientists. The distinguished author eschews complex mathematics whenever possible and focuses on the physical and functional properties of metal oxides in each chapter. Each of the sixteen chapters featured within the book begins with an abstract and an introduction to the topic, clear explanations are presented with graphical illustrations and relevant equations throughout the book. Numerous supporting references are included, and each chapter is self-contained, making them perfect for use both as a reference and as study material. Readers will learn how and why the field of oxide electronics is a key area of research and exploitation in materials science, electrical engineering, and semiconductor physics. The book encompasses every application area where the functional and electronic properties of various genres of oxides are exploited. Readers will also learn from topics like: Thorough discussions of High-k gate oxide for silicon heterostructure MOSFET devices and semiconductor-dielectric interfaces An exploration of printable high-mobility transparent amorphous oxide semiconductors Treatments of graphene oxide electronics, magnetic oxides, ferroelectric oxides, and materials for spin electronics Examinations of the calcium aluminate binary compound, perovoksites for photovoltaics, and oxide 2Degs Analyses of various applications for oxide electronics, including data storage, microprocessors, biomedical devices, LCDs, photovoltaic cells, TFTs, and sensors Suitable for researchers in semiconductor technology or working in materials science, electrical engineering, and physics, Oxide Electronics will also earn a place in the libraries of private industry researchers like device engineers working on electronic applications of oxide electronics. Engineers working on photovoltaics, sensors, or consumer electronics will also benefit from this book.




Compendium of Surface and Interface Analysis


Book Description

This book concisely illustrates the techniques of major surface analysis and their applications to a few key examples. Surfaces play crucial roles in various interfacial processes, and their electronic/geometric structures rule the physical/chemical properties. In the last several decades, various techniques for surface analysis have been developed in conjunction with advances in optics, electronics, and quantum beams. This book provides a useful resource for a wide range of scientists and engineers from students to professionals in understanding the main points of each technique, such as principles, capabilities and requirements, at a glance. It is a contemporary encyclopedia for selecting the appropriate method depending on the reader's purpose.




The Physics of Semiconductors


Book Description

The 4th edition of this highly successful textbook features copious material for a complete upper-level undergraduate or graduate course, guiding readers to the point where they can choose a specialized topic and begin supervised research. The textbook provides an integrated approach beginning from the essential principles of solid-state and semiconductor physics to their use in various classic and modern semiconductor devices for applications in electronics and photonics. The text highlights many practical aspects of semiconductors: alloys, strain, heterostructures, nanostructures, amorphous semiconductors, and noise, which are essential aspects of modern semiconductor research but often omitted in other textbooks. This textbook also covers advanced topics, such as Bragg mirrors, resonators, polarized and magnetic semiconductors, nanowires, quantum dots, multi-junction solar cells, thin film transistors, and transparent conductive oxides. The 4th edition includes many updates and chapters on 2D materials and aspects of topology. The text derives explicit formulas for many results to facilitate a better understanding of the topics. Having evolved from a highly regarded two-semester course on the topic, The Physics of Semiconductors requires little or no prior knowledge of solid-state physics. More than 2100 references guide the reader to historic and current literature including original papers, review articles and topical books, providing a go-to point of reference for experienced researchers as well.