Antimony telluride is an

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

Sb₂Te₃. As is true of other pnictogen chalcogenide layered materials, it is a grey

crystalline solid A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...

with layered structure. Layers consist of two atomic sheets of antimony and three atomic sheets of

tellurium Tellurium is a chemical element with the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...

and are held together by weak

van der Waals force In molecular physics, the van der Waals force is a distance-dependent interaction between atoms or molecules. Unlike ionic or covalent bonds, these attractions do not result from a chemical electronic bond; they are comparatively weak and th ...

s. Sb₂Te₃ is a narrow-gap semiconductor with a band gap 0.21 eV; it is also a topological insulator, and thus exhibits thickness-dependent physical properties.

Crystalline structure

Sb₂Te₃ has a rhombohedral crystalline structure. The crystalline material comprises atoms covalently bonded to form 5 atom thick sheets (in order: Te-Sb-Te-Sb-Te), with sheets held together by van der Waals attraction. Due to its layered structure and weak inter-layer forces, bulk antimony telluride may be mechanically exfoliated to isolate single sheets.

Synthesis

Although antimony telluride is a naturally occurring compound, select stoichiometric compounds may be formed by the reaction of

antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient time ...

with

at 500–900 °C. :2 Sb(l) + 3 Te(l) → Sb₂Te₃(l)

Applications

Like other

binary Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that t ...

chalcogenides of antimony and bismuth, Sb₂Te₃ has been investigated for its

semiconductor A semiconductor is a material which has an electrical resistivity and conductivity, electrical conductivity value falling between that of a electrical conductor, conductor, such as copper, and an insulator (electricity), insulator, such as glas ...

properties. It can be transformed into both ''n''-type and ''p''-type semiconductors by doping with an appropriate

dopant A dopant, also called a doping agent, is a trace of impurity element that is introduced into a chemical material to alter its original electrical or optical properties. The amount of dopant necessary to cause changes is typically very low. When ...

. Doping Sb₂Te₃ with iron introduces multiple Fermi pockets, in contrast to the single frequency detected for pure Sb₂Te₃, and results in reduced carrier density and mobility. Sb₂Te₃ forms the pseudobinary

intermetallic An intermetallic (also called an intermetallic compound, intermetallic alloy, ordered intermetallic alloy, and a long-range-ordered alloy) is a type of metallic alloy that forms an ordered solid-state compound between two or more metallic elemen ...

system germanium-antimony-tellurium with

germanium telluride Germanium telluride (GeTe) is a chemical compound of germanium and tellurium and is a component of chalcogenide glasses. It shows semimetallic conduction and ferroelectric behaviour. Germanium telluride exists in three major crystalline forms, ro ...

, GeTe. Like

bismuth telluride Bismuth telluride (Bi2Te3) is a gray powder that is a compound of bismuth and tellurium also known as bismuth(III) telluride. It is a semiconductor, which, when alloyed with antimony or selenium, is an efficient thermoelectric material for refriger ...

, Bi₂Te₃, antimony telluride has a large

thermoelectric effect The thermoelectric effect is the direct conversion of temperature differences to electric voltage and vice versa via a thermocouple. A thermoelectric device creates a voltage when there is a different temperature on each side. Conversely, when ...

and is therefore used in solid state refrigerators.

References

{{Tellurides Antimony(III) compounds Tellurides