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

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. During and at the end of the course, students 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 predictions 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

PART I: Electronic Structure of Metals, Semiconductors, and Insulators Core Concepts: • Which electrons determine the properties of materials? • How do electrons move in solids? • What determines if a material conducts electricity or not? Topics: • Review of classical concepts: Electric fields and currents Ohm’s Law and the Drude model: a particle-based view of electric conduction Hall effect: electron motion in the presence of a magnetic field Thermoelectric effects: turning heat into electricity and vice versa • Quantum concepts: Electron bands: the key to understanding electrical and optical properties Fermi energy and Fermi surface: where the action happens Density of states: how many electrons can have a given energy. ________________________________________ PART II: Semiconductors – Materials, Concepts and Devices Core Concepts: • How can we control electrical properties by design in semiconductors? • Why are these materials the basis for modern electronics? Topics: • Bandgap: the energy separation between occupied and empty states • Effective mass approximation: electrons aren’t free, but we can model them as if they were • Charge carrier density and dynamics: Temperature effects Doping to tune carrier density Drift vs. diffusion of carriers • Devices: Diodes and transistors: building blocks of electronics Circuit applications: from signal control to logic gates ________________________________________ PART III: Dielectric Properties of Insulators Core Concepts: • How do insulators store and respond to electric fields? • What happens at the atomic level when a material is electrically polarized? Topics: • Electric dipoles: asymmetric charge distributions within atoms and molecules • Types of polarization: Electronic (displacement of electrons) Ionic (shift of atoms) Molecular (orientation of dipolar molecules) • Electric field interactions: What is the electric field inside and outside a dielectric material What are the implications for electric capacitors How does electric breakdown occurs in different materials? Frequency-dependent response and dielectric permittivity ________________________________________ PART IV: Interaction of Electromagnetic Waves with Matter Core Concepts: • How do electromagnetic waves interact and propagate within different media? • Why do materials look transparent, colored, or reflective? • Why are polarization and frequency of electromagnetic waves important? Topics: • Revision of electromagnetic waves • Light-matter interaction: Microscopic origin of refractive index Reflection, refraction, and absorption of electromagnetic waves • Anisotropy and optical activity: materials that behave differently depending on the direction or polarization of light • Optical properties of insulating crystals, glasses, metals, and semiconductors _______________________________________ PART V: Photonic Devices Core Concepts: • How do materials convert light to electricity or vice versa? • What material properties are essential for optoelectronic devices? Topics: •Photodiodes and solar cells: light in, current out • LEDs and lasers: current in, light out • Displays and fiber optics: controlling and guiding light with materials ________________________________________ PART VI: Magnetism Core Concepts: • Where does magnetism come from? • How do collective magnetic properties in materials emerge from the atomic spins and orbital moments? Topics: • Magnetic moments: from individual atoms to collective behavior • Types of magnetism: Diamagnetism, paramagnetism, ferromagnetism, antiferromagnetism • Magnetic order vs temperature • Magnetic domains and anisotropy: shaping and controlling magnetization • Magnetization processes: hysteresis curves, energy loss • Applications: Hard and soft magnets in motors, sensors, data storage

Resources