Thermoelectric effect
The thermoelectric effect has a macroscopic electric dipole moment caused by spontaneous polarization, and a crystal with a large thermal expansion coefficient is called a thermoelectric crystal. The pyroelectric crystal in the state of spontaneous polarization has the bound charge formed by the polarization on the surfaces of the positive and negative ends of the electric dipole moment, but it does not show the charging property due to the adsorption of different ions in the air. When the temperature changes, the volume of the thermoelectric crystal changes significantly, which leads to a significant change in the polarization intensity, destroying the electrical neutrality of the surface, and the excess charge adsorbed on the surface will be released. This phenomenon is called the thermoelectric effect. Both artificially polarized ferroelectrics and electrets have a thermoelectric effect. The thermoelectric effect has been used in infrared detection and thermal imaging technology.