Information about the course, questionnaire about the interests of students
Text: "Electronic Structure: Basic theory and practical methods," R. M. Martin (Cambridge University Press, 2004).
Reading: Text: Chapters 1 and 2.
This first lecture is a general introduction to the observed properties of electrons in matter, and to key issues in current theory of electronic structure. The overview stresses physical phenomena with a minimum of equations, following Chapters 1 and 2 of the text. The goal is to give a qualitative introduction to the issues presented by the fascinating array of phenomena and the role of electronic structure in providing fundamental understanding and predictive power.
- Development of Electronic Structure
- 1920's: Quantum Mechanics: rapid understanding of basic properties of electrons in materials
- 1930's: Initial steps in developments of all the current methods
- 1940's: Advent of Electronic computers and Solid State Electronics
- 1950's: Band calculations with computers; Many-Body Theory of Electrons in Metals;Fermi Liquid Theory
- 1960's: New Approaches to the many-body problem
Ground state methods: Density Functional Theory and Quantum Monte Carlo
Excited State methods: "GW" formulation of many-body perturbation theory.- 1970's: Emergence of Computation in Electronic Structure
- 1980's: New Discoveries (STM, QHE, C60, Hi-Tc, ..) and Theoretical Methods (Car-Parrinello; "GW", ..)
- 1990's: Discoveries Continue; Materials Computation Comes of Age
- Future: Challenges for realistic simulations of materials; correlated electrons
- Classification of Electronic Properties of Materials: Ground State vs. Excited State Properties
- Ground State Properties
- Crystal Structure and binding energy
- Elastic Constants; phonons in adiabatic approximation
- Magnetic Structure at T=0
- Transitions between crystal structures
- Excited State Properties
- One-electron addition and removal spectra
- Optical properties
- Nature of Electronic States in Materials: Delocalized Band-like vs. Localized Atomic-like
- Examples of materials
Greatest Challenge: Intermediate systems
- Wide band: "simple" metals, semiconductors, ...
- Narrow band: Rare earths, some actinides, some molecular systems, ...
- Intermediate Cases: Transition metals, transition metal oxides, some actinides, some molecular systems, ...
- Key Steps in Theoretical Work
- Independent Particle Approaches
- Density Functional Methods
- Many-Body Approaches
- Quantum Monte Carlo methods for the ground state
- Excited States: Quasiparticles and Green's functions methods
- Simulations of Materials
- Srongly-correlated Electron Problems
- Outline of course