Introduction to Solid State Physics

TL;DR

This lecture introduces fundamental concepts of solid state physics, focusing on single-particle phenomena, collective excitations like phonons and electrons, and providing a conceptual framework for understanding many-body systems in solids.

Contribution

It offers an accessible overview emphasizing basic ideas and simplified models to explain collective excitations and the phenomenology of many-body physics in solids.

Findings

Introduction of quasi-particles and their dispersion relations

Explanation of phonons as quantized lattice vibrations

Discussion of electrons as quantized charge excitations

Abstract

Lecture Goals: (i) Introduction to the basic concepts, meaning that the emphasis is, in the first instance, on the single-particle aspects. (ii) Service for Experimental Solid State Physics. (iii) Emphasis on the explanation of concepts and basic ideas, not always quantitative, justification of the use of simplified `model Hamiltonians'. (iv) Raise some understanding why many-body physics is mostly phenomenology. (v) Convey the following main idea: (Collective) elementary excitations are `quasi-particles' characterized by their dispersion relation $\mathbf{p} \mapsto \varepsilon (\mathbf{p})$ and by certain quantum numbers like spin and charge. The most important two are `the phonon' (= quantized lattice vibration) and `the electron' (= quantized charge excitation of the solid, which has as much to do with the electron of elementary particle physics as water waves have to do with water).