Electric polarization

Electric polarization is the separation or alignment of positive and negative charges within matter, described by electric dipole moment per unit volume. It can arise from an applied field or persist spontaneously.

Electric dipole moment: A vector measure of the separation of positive and negative charge in a system. Polarization density sums microscopic dipole moments across a material.
Electric field: A vector field that gives the force per unit positive charge at each point in space. An applied field can displace charges or orient dipoles in matter.
Capacitor: A device that stores electrical energy by separating charge across an insulating region. Polarization increases capacitance by reducing the field produced by a given free charge.
Electric conduction: The transport of electric charge through a material under an electric field. Polarization displaces bound charge, whereas conduction transports charge through the material.
Electronic polarization: A material response in which an electric field shifts an atom’s electron cloud relative to its nucleus. This rapid response occurs in essentially all dielectric materials.
Dielectric: An electrical insulator whose response to an electric field includes the displacement of bound charge. Dielectrics are the materials whose polarization response is commonly measured.
Ferroelectricity: A property of materials with a spontaneous electric polarization that can be reversed by an applied field. Its switchable polarization enables memory and sensing devices.
Spontaneous polarization: A nonzero electric polarization that exists in a material without an applied electric field. It distinguishes internally ordered polarization from field-induced response.
Ionic polarization: A dielectric response caused by oppositely charged ions shifting relative to one another. This lattice-scale displacement contributes to polarization in ionic solids.
Electric susceptibility: A dimensionless measure of how strongly a material polarizes in response to an electric field. In a linear dielectric, susceptibility relates polarization to field strength.

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