Engineering Physics and Solid State Physics

A unit cell is the smallest repeating unit of a crystal lattice that retains the symmetry of the crystal.

Semiconductors have low electrical conductivity at low temperatures, but their conductivity increases with increasing temperature.

The energy gap in a semiconductor is typically small, allowing electrons to be excited from the valence band to the conduction band with a relatively small amount of energy.

A diode is a semiconductor device that allows current to flow in one direction but not the other.

Superconductivity is the phenomenon in which a material loses all electrical resistance below a certain critical temperature.

Type I superconductors are those that exhibit a sharp transition from the superconducting state to the normal state at a critical magnetic field.

The Meissner effect is the expulsion of magnetic flux from a superconductor when it is cooled below its critical temperature.

Ferromagnetic materials have a strong attraction between magnetic moments, causing them to align in the same direction.

The Curie temperature is the temperature at which a ferromagnetic material loses its ferromagnetism and becomes paramagnetic.

Cubic, hexagonal, tetragonal, and orthorhombic are all types of crystal structures.

The Bravais lattice is a lattice with a repeating pattern of points that represent the positions of atoms or molecules in a crystal.

Crystalline, amorphous, polycrystalline, and metallic are all types of solids.

Crystalline solids have a regular arrangement of atoms, while amorphous solids do not. This difference in structure gives rise to different properties, such as density, hardness, and transparency.

Metals have high electrical conductivity because they contain a large number of free electrons.

The Fermi level is the highest energy level that is occupied by electrons at absolute zero.