Electronic, Optical and Magnetic Properties of Materials

Abstract

This course provides physical foundations to understand the response of different classes of materials to electromagnetic fields, focusing on their electrical, optical, and magnetic properties, and on the basic functioning of devices that exploit such properties. The lectures build on classical and quantum mechanical concepts to provide microscopic understanding and modelling.

Objective

Student should be able to: - Apply fundamental concepts in solid state physics to describe and explain the behavior of different types of materials, including the ability to make semi-quantitative assertions about relevant physical quantities. - Analyze and evaluate different models and approaches to describe specific material properties, and appreciate the pertinence of these models to real-world applications, including the ability to make numerical estimates of the relevant parameters. - Explain the working principles of a range of devices that take advantage of the physical properties of materials, including electronic, photonic, and magnetic devices. - Develop an appreciation for the role of solid state physics in modern society and technology, and understand the importance of continued research and development in this field for future technological advancements.

Content

Understanding the electronic properties of solids is at the heart of modern society and technology. The aim of this course is to provide fundamental physical concepts that allow one to relate the electronic structure of different types of materials to their electrical, optical, and magnetic behavior as well as the functioning of basic electronic, photonic, and magnetic devices. Beyond fundamental curiosity, such level of understanding is required in order to develop and appropriately describe new classes of materials for future technology applications. The course is divided in six parts. PART I: The electronic structure of metals, semiconductors, and insulators Revision of classical concepts: electric fields and currents, Ohm’s and Drude’s model of electrical conductivity, Hall effect, thermoelectric effects. Revision of quantum mechanical concepts: Electron bands, Fermi statistics, Fermi energy and Fermi surface, density of states in k-space and as a function of energy. PART II: Semiconductors: concepts and devices Valence and conduction electron bands. Material parameters affecting the bandgap energy. Effective mass approximation. Charge carrier density as a function of temperature and doping. Electrical conductivity and mobility. Drift and diffusion currents. Diodes and transistors. Basic applications in electrical circuits. PART III: Dielectric properties of insulators The electric dipole. Microscopic origin of dipoles in matter: Electronic, ionic, molecular polarization. Electric field inside and outside dielectric materials. Connection between macroscopic and microscopic polarization. Dielectric breakdown. Electric polarization induced by time-dependent electric fields. Dielectric permittivity as a function of frequency. PART IV: Interaction of electromagnetic waves with matter The electromagnetic (EM) spectrum. Electromagnetic waves in vacuum; Energy, momentum, and angular momentum of EM waves; Sources of EM radiation; EM waves in matter. The refractive index. Transmission, Reflection, and Refraction from a microscopic point of view. Optical anisotropy, Optical activity, Dichroism. Optical properties of crystalline insulators and semiconductors, glasses, and metals. PART V: Photonic devices Photodiodes, photovoltaic cells, light emitting devices (LEDs), Laser diodes, displays, optical fibers. PART VI: Magnetism Classical magnetic phenomena. Quantum mechanical origin of magnetism. Magnetic moments in atoms and solids, exchange interaction, magnetic anisotropy. Diamagnetism, paramagnetism, ferromagnetism. Magnetic domains. Magnetization curves and magnetization processes. Soft and hard magnets. Applications of magnetic materials.

Resources