Bismuth Antimonide

Bismuth antimonide particles are a crystalline powdery granular material with a light to dark grey appearance and a cage-like crystal structure (i.e., a cubic cobaltite-like structure). It is an important functional material that serves as a superconductor and semiconductor at low temperatures, has applications in thermoelectric devices, and is an important topological insulator in nanoelectronics.

Properties

Chemical formula: BiSb

Molecular weight: 330.74 g/mol

Precise mass: 329.884214

Appearance: Bismuth antimonide is a grey-black solid powder, ranging from light grey to dark grey in colour.

Density: 8.31 g/cm³

Crystal structure: It has a cage-like crystal structure with hexagonal crystal system and belongs to cubic cobaltite-like structure (skutterudite). Its lattice constant a = 4.546 Å, c = 11.860 Å (1 Å = 0.1 nm).

Solubility: Bismuth antimonide is insoluble in water.

SEMICONDUCTOR CHARACTERISTICS: Exhibits the electrical properties of a semiconductor over a range of temperatures. At 40 K, the electron mobility varies from 0.49×10⁶ /(V・s) (antimony concentration 0) to 0.24×10⁶ /(V・s) (antimony concentration 7.2%) when the antimony concentration is varied, which is much higher than that of common semiconducting silicon (1400 /(V・s)) at room temperature.
Topological insulator properties: some bismuth antimonide materials, especially Bi₀. ₉Sb₀. ₁, were the first experimentally observed three-dimensional topological insulators that are insulating inside the material but have conducting states on the surface, which opens up possibilities for future spintronics applications.

Superconducting properties: The maximum superconducting temperature (critical temperature Tc) is about 2 K in the thin film state at a thickness of 150 – 1350 Å. The single crystal state can superconduct at slightly higher temperatures. The critical magnetic field (the maximum field that can be repelled by a superconductor) is 1.6 T at a temperature of 4.2 K. The maximum superconducting temperature (Tc) is about 2 K in the single-crystal state.

Thermal Properties: Used in thermoelectric devices, the thermoelectric figure of merit (ZT) peaks at 6.5 at 80 K for a specific composition of bismuth antimonide (x = 15%), and the Seebeck coefficient (the ratio of the potential difference between the two ends of the material to the temperature difference between the two sides) at this temperature is -140 μV/K, which is less than the Seebeck coefficient for pure bismuth (-50 μV/K).

Applications

Thermoelectric material: Bismuth antimonide is a thermoelectric material with good performance at low temperatures. It can convert thermal energy directly into electrical energy, or conversely convert electrical energy into thermal energy, and can be used to make small thermoelectric generators, refrigeration devices, etc. For example, in some special environments, such as space probes, unmanned monitoring equipment in remote areas, etc., the use of thermoelectric materials can be converted from heat energy in the environment into electrical energy to provide electrical support for the equipment; in some small electronic devices with high requirements for temperature control, bismuth antimonide thermoelectric materials can be used to achieve precise temperature control.

Topological insulator: Bismuth antimonide is a typical three-dimensional topological insulator material. In this material, the interior is insulating, but a conducting state exists on the surface. This gives it great potential for applications in the field of spintronics, where it can be used to develop novel spintronic devices such as spin field effect transistors and spin valves. These devices utilise the spin property of electrons for information storage and processing, and have higher information processing speeds and lower energy consumption than conventional electronic devices.

Superconducting materials: In a thin film state and within a certain thickness range, bismuth antimonide can exhibit superconducting properties at lower temperatures. Although its superconducting critical temperature is relatively low, the superconducting property of bismuth antimonide still has important application value in some special application scenarios which are sensitive to magnetic field, such as superconducting quantum interferometer, superconducting magnet and other devices.

Semiconductor materials: bismuth antimonide exhibits the electrical properties of semiconductor in a certain temperature range, which can be used to manufacture semiconductor devices, such as diodes and transistors. Moreover, due to its high electron mobility, it has potential application advantages in some semiconductor devices that require high electron transfer speed.

Scientific research field: Due to its unique physical properties, bismuth antimonide is often used as a research object in materials science, physics and other scientific research fields to explore the physical properties and applications of new materials. For example, through the study of bismuth antimonide, researchers can gain an in-depth understanding of the basic physical problems in the fields of topological insulators, thermoelectric materials, etc., and provide theoretical support for the development of new functional materials.