Germanium telluride is a chemical compound of germanium

Germanium

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. The isolated element is a semiconductor, with an appearance most similar to elemental silicon....

 and tellurium and is a component of chalcogenide glass

Chalcogenide glass

A chalcogenide glass is a glass containing one or more chalcogenide elements. These are Group 16 in the periodic table e.g. sulfur, selenium or tellurium. Such glasses are covalently bonded materials and may be classified as network solids. In effect, the entire glass matrix acts like an...

es. It shows semimetallic conduction and ferroelectric behaviour.

Germanium telluride exists in three major crystalline forms, room-temperature α (rhombohedral) and γ (orthorhombic) structures and high-temperature β (cubic

Sodium chloride

Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...

, rocksalt-type) phase; α phase being most common.