Tellurium binds bismuth- telluride and gallium-arsenide thermoelectric material

摘要

Bismuth telluride (Bi_2Te_3) and gallium arsenide (GaAs) make quite a pair, combining to form a highly efficient electronics-cooling thermoelectric material. Although scientists have been using this material pair for years, how the two materials stick together has remained a mystery. Now, with the aid of high-powered, highly sensitive imaging systems, researchers at North Carolina State University have found a definitive answer. Most inorganic compounds are held together with chemical bonds, says James LeBeau, a professor of materials science and engineering at North Carolina State University. But for some time, scientists have known that Bi_2Te_3 and GaAs do not follow this pattern. Instead, the two materials combine through van der Waals interactions that are considerably weaker than a chemical bond. Just how the bond is formed and how it manages to hold the system together was the real mystery, says LeBeau.