First discovery of a natural topological insulator

Mar 06, 2013
The mineral Kawazulite is a natural “topological insulator,” a material that could have applications in a new genre of supercomputers. Credit: American Chemical Society

(Phys.org) —In a step toward understanding and exploiting an exotic form of matter that has been sparking excitement for potential applications in a new genre of supercomputers, scientists are reporting the first identification of a naturally occurring "topological insulator" (TI). Their report on discovery of the material, retrieved from an abandoned gold mine in the Czech Republic, appears in the ACS journal Nano Letters.

Pascal Gehring and colleagues point out that synthetic TIs, discovered only a decade ago, are regarded as a new horizon in materials science. Unlike conventional electrical insulators, which do not conduct electricity, TIs have the unique property of conducting electricity on their surface, while acting as an insulator inside. Although seemingly simple, this type of surface could allow manipulation of the spin of an electron, paving the way for development of a quantum computer. Such a computer would crunch data much faster than today's best supercomputers.

The research team describes discovering that the mineral Kawazulite, found in the Czech gold mine and processed into nanoflakes, is a natural TI. The flakes were so small that thousands would fit inside the dot over an "i." Based on the discovery, natural TIs may exist in other minerals, the report states. Scientists, they recall, once believed that quasi-crystals—topic of the 2011 —were available only synthetically, but those materials recently were discovered in sky-fallen meteorites.

First discovery of a natural topological insulator

The article is titled "A Natural Topological ."

Explore further: Dye-sensitized solar cell absorbs a broad range of visible and infrared wavelengths

More information: A Natural Topological Insulator, Nano Lett., Article ASAP. DOI: 10.1021/nl304583m

Abstract
The earth's crust and outer space are rich sources of technologically relevant materials which have found application in a wide range of fields. Well-established examples are diamond, one of the hardest known materials, or graphite as a suitable precursor of graphene. The ongoing drive to discover novel materials useful for (opto)electronic applications has recently drawn strong attention to topological insulators. Here, we report that Kawazulite, a mineral with the approximate composition Bi2(Te,Se)2(Se,S), represents a naturally occurring topological insulator whose electronic properties compete well with those of its synthetic counterparts. Kawazulite flakes with a thickness of a few tens of nanometers were prepared by mechanical exfoliation. They exhibit a low intrinsic bulk doping level and correspondingly a sizable mobility of surface state carriers of more than 1000 cm2/(V s) at low temperature. Based on these findings, further minerals which due to their minimized defect densities display even better electronic characteristics may be identified in the future.

Related Stories

Blocking infinity in a topological insulator

Feb 08, 2013

(Phys.org)—In bulk, topological insulators (TIs) are good insulators, but on their surface they act as metals, with a twist: the spin and direction of electrons moving across the surface of a TI are locked ...

Engineers show feasibility of superfast materials

Feb 13, 2013

(Phys.org)—University of Utah engineers demonstrated it is feasible to build the first organic materials that conduct electricity on their edges, but act as an insulator inside. These materials, called ...

Recommended for you

A new way to make microstructured surfaces

21 hours ago

A team of researchers has created a new way of manufacturing microstructured surfaces that have novel three-dimensional textures. These surfaces, made by self-assembly of carbon nanotubes, could exhibit a ...

Tough foam from tiny sheets

Jul 29, 2014

Tough, ultralight foam of atom-thick sheets can be made to any size and shape through a chemical process invented at Rice University.

Graphene surfaces on photonic racetracks

Jul 28, 2014

In an article published in Optics Express, scientists from The University of Manchester describe how graphene can be wrapped around a silicon wire, or waveguide, and modify the transmission of light through it.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

ValeriaT
1 / 5 (1) Mar 10, 2013
Interesting is, the samples measured were found in former gold mine in Czech Republic, so our country could become the first source of Obtanium in future.
Cave_Man
1 / 5 (1) Apr 02, 2013
Did these guys not see the terminator movies or what? My laptop works fine, i dont need it to tap into my head as one of its functions. i wonder what a processor made of this would compare to the human brain eh?