New material shares many of graphene`s unusual properties
Baku, April 26 (AZERTAC). Thin films of bismuth-antimony have potential for new semiconductor chips, thermoelectric devices.
Graphene, a single-atom-thick layer of carbon, has spawned much research into its unique electronic, optical and mechanical properties. Now, researchers at MIT have found another compound that shares many of graphene`s unusual characteristics — and in some cases has interesting complementary properties to this much-heralded material.
The material, a thin film of bismuth-antimony, can have a variety of different controllable characteristics, the researchers found, depending on the ambient temperature and pressure, the material`s thickness and the orientation of its growth. The research, carried out by materials science and engineering PhD candidate Shuang Tang and Institute Professor Mildred Dresselhaus, appears in the journal Nano Letters.
Like graphene, the new material has electronic properties that are known as two-dimensional Dirac cones, a term that refers to the cone-shaped graph plotting energy versus momentum for electrons moving through the material. These unusual properties — which allow electrons to move in a different way than is possible in most materials — may give the bismuth-antimony films properties that are highly desirable for applications in manufacturing next-generation electronic chips or thermoelectric generators and coolers.
Such applications remain speculative at this point, Dresselhaus says, because further research is needed to analyze additional properties and eventually to test samples of the material. This initial analysis was based mostly on theoretical modeling of the bismuth-antimony film`s properties.
Until this analysis was carried out, Dresselhaus says, “we never thought of bismuth” as having the potential for Dirac cone properties. But recent unexpected findings involving a class of materials called topological insulators suggested otherwise: Dresselhaus cautions, but adds that the principles are clear and the necessary analysis should take less than a year to carry out.
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