Types and Structure of Crystals
In this chapter we discuss the some of the important properties of solid materials depening on geometrical atomic arrangements and also the interactions that exist among constituent atoms or molecules.
- Crystalline types of solid
- Lattice and lattice translational vector
- Symmetry operations and space groups
- Primitive lattice cell
- Fundamental types of lattices
- Types of crystal structures
- Primitive unit cell
- Wigner-Seitz cell
Crystal Structure from Diffraction
In this chapter we discuss the importance of difffraction phenomena on wave to study the structure of the crystal. Also, some other interesting properties of crystal are discussed.
- Neutron and X-ray diffraction
- Bragg’s law
- Laue method
- Brillouin zone
- Lattice Planes and Miller indices
- Reciprocal lattice
- Geometrical Structure Factor
- Atomic Form Factor
Bonding in Crystals
In this chapter we discuss primarily with the various types of atomic bonding which are determined by the electron structure of the individual atoms.
- Equilibrium lattice constant
- Different types of bonding
- Bonding in Crystals of Inert gases
Defects in Crystals
Crystallographic defects are interruptions of regular patterns in crystalline solids. They are common because positions of atoms or molecules at repeating fixed distances determined by the unit cell parameters in crystals, which exhibit a periodic crystal structure, are usually imperfect. In this chapter we discuss within following topics;
- Lattice vacancies, colour-centers
- Alloy, slip, types of dislocations
- Burgers vector
- Dislocation and crystal growth
Bonding in Crystals
In this chapter we discuss the properties of the solid that is determined by the phonon wave.
- Lattice vibration
- Phonon spectrum
- lattice specific heat: Dulong and Petits relation
- Einstein theory, Debye’s theory
- Thermal conductivity & resistivity of phonon gas
- Umklapp processes
Free Electron Theory
In solid-state physics, the free electron model is a simple model for the behaviour of charge carriers in a metallic solid. Our discussion under this topic includs following topics;
- Free electron theory of metals
- Density of states
- Fermi energy
- Free electron theory of metals
- Electron specific heat, relaxation time
- Mean free path, mobility, thermal conductivity & conductivity
- Wiedmann-Franz law
- Hall effect
Band Structure of Crystals
Band structure is only an approximation to the quantum state of a solid, which applies to solids consisting of many identical atoms or molecules bonded together. In this topic we discuss different model of band structure. Which are given below.
- Bloch Functions
- Different types of bonding
- Energy bands in 1D
- Energy-wave vector curves in 3D
- The tight binding method – Linear combination atomic orbitals
- Valence and conduction band
- Conductor, insulator and semiconductor
- Fermi surfaces
- Number of orbitals in a band
Semiconductors
A semiconductor material has an electrical conductivity value falling between that of a conductor, such as metallic copper, and an insulator, such as glass. Its resistance falls as its temperature rises; metals are the opposite. In this chapter we discuss following topics;
- Types of semiconductors
- Impurity conductivity
- Thermal ionization of donors and acceptors; Mobility
Superconductivity
Superconductivity is the set of physical properties observed in certain materials, wherein electrical resistance vanishes and from which magnetic flux fields are expelled. This chapter includes the following topics;
- General properties of superconductors
- Zero resistivity
- Critical temperature, Critical magnetic field
- Meissner effect
- Type I and type II Superconductors
Dielectric properties
A dielectric is an electrical insulator that can be polarized by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the material as they do in an electrical conductor but only slightly shift from their average equilibrium positions causing dielectric polarization. Following properties of dielectric materials are discussed in this chapter;
- Dielectric constant and polarizability
- Electronic, ionic and orientational polarizabilities
- Electric Susceptibility
- Clausius Mosotti Equation
Magnetism
Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. Following topics are discussed in this chapter;
- Dia-, Para-, Ferri-,Antiferro- and Ferromagnetic Materials
- Classical Langevin Theory of dia – and Paramagnetic Domains
- Quantum Mechanical Treatment of Paramagnetism
- Curie’s law
- Weiss’s Theory of Ferromagnetism and Ferromagnetic Domains