Leitfähigkeitsänderungen

Leitfähigkeitsänderungen, also known as conductivity changes, refer to variations in the electrical conductivity of a material. Electrical conductivity is a measure of a material's ability to conduct electric current. It is the reciprocal of resistivity, which measures a material's opposition to current flow. Leitfähigkeitsänderungen can occur due to various factors, including temperature, pressure, the presence of impurities, structural defects, or external fields.

In metals, conductivity generally decreases with increasing temperature because atomic vibrations become more energetic, scattering free electrons. Semiconductors, however, often exhibit an increase in conductivity with temperature, as more charge carriers are thermally excited into the conduction band. Pressure can also influence conductivity, particularly in materials where compression alters interatomic distances and electronic band structures.

The introduction of impurities, a process known as doping, is a fundamental technique for controlling the conductivity of semiconductors. Alloying in metals also leads to changes in conductivity, typically a decrease compared to the pure constituent metals due to increased scattering of electrons by different atomic species. Phase transitions and changes in the crystalline structure of a material can also result in significant conductivity changes.

Understanding and controlling leitfähigkeitsänderungen is crucial in many technological applications, such as the design of electronic components, sensors, and thermoelectric devices. For instance, thermistors are sensors that exploit the predictable temperature dependence of semiconductor conductivity to measure temperature. Similarly, strain gauges utilize the change in resistivity (and thus conductivity) of a material when it is mechanically deformed.