New multifunctional topological insulator material with combined superconductivity

September 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 insulator is insulating inside the bulk like a normal insulator, while on the surface it shows conductivity like a metal. When a topological insulator 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 fermions 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 in Germany 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."

Binghai Yan, Martin Jansen, Claudia Felser, A large-energy-gap oxide topological insulator based on the superconductor BaBiO3, Nature Physics, 22 September 2013,

Johannes Gutenberg Universitaet Mainz

Related Superconductivity Articles from Brightsurf:

New kind of superconductivity discovered
Superconductivity is a phenomenon where an electric circuit loses its resistance and becomes extremely efficient under certain conditions.

Room temperature superconductivity creeping toward possibility
The possibility of achieving room temperature superconductivity took a tiny step forward with a recent discovery by a team of Penn State physicists and materials scientists.

A 'breath of nothing' provides a new perspective on superconductivity
Zero electrical resistance at room temperature? A material with this property, i.e. a room temperature superconductor, could revolutionize power distribution.

New Princeton study takes superconductivity to the edge
The existence of superconducting currents, or supercurrents, along the exterior of a superconductor, has been surprisingly hard to find.

Superconductivity: It's hydrogen's fault
Last summer, it was discovered that there are promising superconductors in a special class of materials, the so-called nickelates.

How a magnet could help boost understanding of superconductivity
Physicists have unraveled a mystery behind the strange behavior of electrons in a ferromagnet, a finding that could eventually help develop high temperature superconductivity.

New study explains why superconductivity takes place in graphene
Theoretical physicists take important step in development of high temperature superconductors.

Better studying superconductivity in single-layer graphene
A new study published in EPJ B demonstrates that an existing technique is better suited for probing superconductivity in pure, single-layer graphene than previously thought.

Stressing metallic material controls superconductivity
No strain, no gain -- that's the credo for Cornell researchers who have helped find a way to control superconductivity in a metallic material by stressing and deforming it.

First report of superconductivity in a nickel oxide material
Scientists at SLAC and Stanford have made the first nickel oxide material that shows clear signs of superconductivity - the ability to transmit electrical current with no loss.

Read More: Superconductivity News and Superconductivity Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to