Researchers present new multifunctional topological insulator material with combined superconductivity

Sep 25, 2013

Most materials show one function, for example, a material can be a metal, a semiconductor, or an insulator. Metals such as copper are used as conducting wires with only low resistance and energy loss. Superconductors are metals which can conduct current even without any resistance, although only far below room temperature. Semiconductors, the foundation of current computer technology, show only low conduction of current, while insulators show no conductivity at all. Physicists have recently been excited about a new exotic type of materials, so-called topological insulators.

A topological is insulating inside the bulk like a normal insulator, while on the surface it shows conductivity like a metal. When a is interfaced with a superconductor, a mysterious particle called Majorana fermion emerges, which can be used to fabricate a quantum computer that can run much more quickly than any current computer. Searching for Majorana based on a topological insulator–superconductor interface has thus become a hot race just very recently.

Computer-based materials design has demonstrated its power in scientific research, saving resources and also accelerating the search for new materials for specific purposes. By employing state-of-art materials design methods, Dr. Binghai Yan and his collaborators from the Max Planck Institute for Chemical Physics of Solids and Johannes Gutenberg University Mainz (JGU) have recently predicted that the oxide compound BaBiO3 combines two required properties, i.e., topological insulator and superconductivity. This material has been known for about thirty years as a high-temperature superconductor of Tc of nearly 30 Kelvin with p-type doping. Now it has been discovered to be also a topological insulator with n-type doping. A p-n junction type of simple device assisted by gating or electrolyte gating is proposed to realize Majorana fermions for quantum computation, which does not require a complex interface between two materials.

In addition to their options for use in quantum computers, topological insulators hold great potential applications in the emerging technology of spintronics and thermoelectrics for energy harvesting. One major obstacle for widespread application is the relatively small size of the bulk band gap, which is typically around 0.3 electron-volts (eV) for previously known topological insulator materials. Currently identified material exhibits a much larger energy-gap of 0.7 eV. Inside the energy-gap, metallic topological surface states exist with a Dirac-cone type of band structures.

The research leading to the recent publication in Nature Physics was performed by a team of researchers from Dresden and Mainz around the theoretical physicist Dr. Binghai Yan and the experimental chemists Professor Martin Jansen and Professor Claudia Felser. "Now we are trying to synthesize n-type doped BaBiO3," said Jansen. "And we hope to be soon able to realize our idea."

Explore further: Pseudoparticles travel through photoactive material

More information: Binghai, Y., Jansen, M. and Felser, C. A large-energy-gap oxide topological insulator based on the superconductor BaBiO3, Nature Physics, 22 September 2013. DOI: 10.1038/nphys2762

Related Stories

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 ...

Novel topological crystalline insulator shows mass appeal

Aug 29, 2013

Disrupting the symmetrical structure of a solid-state topological crystalline insulator creates mass in previously mass-less electrons and imparts an unexpected level of control in this nascent class of materials, an international ...

Recommended for you

Pseudoparticles travel through photoactive material

Apr 23, 2015

Researchers of Karlsruhe Institute of Technology (KIT) have unveiled an important step in the conversion of light into storable energy: Together with scientists of the Fritz Haber Institute in Berlin and ...

From metal to insulator and back again

Apr 22, 2015

New work from Carnegie's Russell Hemley and Ivan Naumov hones in on the physics underlying the recently discovered fact that some metals stop being metallic under pressure. Their work is published in Physical Re ...

Electron spin brings order to high entropy alloys

Apr 22, 2015

Researchers from North Carolina State University have discovered that electron spin brings a previously unknown degree of order to the high entropy alloy nickel iron chromium cobalt (NiFeCrCo) - and may play ...

Expanding the reach of metallic glass

Apr 22, 2015

Metallic glass, a class of materials that offers both pliability and strength, is poised for a friendly takeover of the chemical landscape.

Electrons move like light in three-dimensional solid

Apr 22, 2015

Electrons were observed to travel in a solid at an unusually high velocity, which remained the same independent of the electron energy. This anomalous light-like behavior is found in special two-dimensional ...

Quantum model helps solve mysteries of water

Apr 20, 2015

Water is one of the most common and extensively studied substances on earth. It is vital for all known forms of life but its unique behaviour has yet to be explained in terms of the properties of individual ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.