Solid-state physics, the largest branch of condensed matter physics, is the study of rigid matter, or solids. The bulk of solid-state physics theory and research is focused on crystals, largely because the periodicity of atoms in a crystal--its defining characteristic--facilitates mathematical modeling, and also because crystalline materials often have electrical, magnetic, optical, or mechanical properties that can be exploited for engineering purposes.
The framework of most solid-state physics theory is the Schrödinger (wave) formulation of non-relativistic quantum mechanics. Bloch's Theorem, which characterizes the wavefunctions of electrons in a periodic potential, is an important starting point for much analysis. Since Bloch's Theorem applies only to periodic potentials, and since unceasing random movements of atoms in a crystal disrupt periodicity, Bloch's Theorem is only an approximation, but it has proven to be a tremendously valuable approximation, without which most solid-state physics analysis would be intractable. Deviations from periodicity are treated by quantum mechanical perturbation theory.
|General subfields within physics||Edit|
Classical mechanics | Condensed matter physics | Continuum mechanics | Electromagnetism ||
General relativity | Particle physics | Quantum field theory | Quantum mechanics |
Solid state physics | Special relativity | Statistical mechanics | Thermodynamics