Seebeckkoefficient

The Seebeck coefficient, also known as the thermoelectric power or thermopower, is a material property that describes the voltage generated per unit temperature difference across a material. It is a fundamental parameter in thermoelectricity, which is the direct conversion of temperature differences to electric voltage and vice versa. The Seebeck coefficient is named after the German physicist Thomas Johann Seebeck, who discovered the thermoelectric effect in 1821.

The Seebeck coefficient is typically denoted by the Greek letter alpha (α) and has units of volts per kelvin (V/K). It is defined as the ratio of the induced electromotive force (EMF) to the temperature difference between two junctions in a thermocouple. The Seebeck coefficient can be either positive or negative, depending on the material and the direction of the temperature gradient. Materials with a positive Seebeck coefficient are called n-type (negative) thermoelectrics, while those with a negative Seebeck coefficient are called p-type (positive) thermoelectrics.

The Seebeck coefficient is influenced by several factors, including the type and concentration of charge carriers (electrons or holes) in the material, the band structure, and the scattering mechanisms. In metals, the Seebeck coefficient is generally small and negative, while in semiconductors, it can be much larger and either positive or negative, depending on the doping type.

The Seebeck coefficient is a crucial parameter in the design and optimization of thermoelectric devices, such as thermoelectric generators and coolers. By selecting materials with appropriate Seebeck coefficients and optimizing their properties, it is possible to achieve efficient thermoelectric energy conversion and temperature control.