Topological superconductor in sight
Researchers from the FOM foundation, Institute of Physics of the University of Amsterdam and the National Institute for Materials Science in Tsukuba (Japan) have demonstrated that the electrons in a topological superconductor behave in an unusual manner. The electrons merged into exotic pairs with unusual quantum properties. The interest for topological superconductors is considerable, as they could serve as fundamental building blocks of future quantum computers. The researchers will shortly publish their findings in the renowned journal Physical Review Letters.
Topological insulators form a new group of electronic materials with strange properties: on the inside they conduct no current, but on the surface or edges they do. Unusually the current on the surface is ‘topologically protected’: normal scattering processes for the electrons are switched off and this means that there are potential future applications in spintronics, a new type of electronics. Even more exciting is that with a minor adjustment to their composition, some topological insulators transform into their counterpart: superconductors.
The research team led by Dr. Anne de Visser examined the topological superconductor CuxBi2Se3, which becomes superconducting at a temperature of about 3.5 Kelvin. Electrical transport measurements reveal that the transition temperature depends in a unique and universal manner on an externally applied magnetic field. These findings point to the fact that the electrons pair to become superconducting spin-triplet pairs, as opposed to spin-singlet pairs as in most known superconductors. This means that CuxBi2Se3 fulfils one of the most important conditions for topological superconduction.
Topological superconductors are an important step in the realisation of Majorana fermions. These quasi particles are the favourite contenders in the competition to construct robust quantum bits, due to their exceptional statistical properties and the weak link with the outside world. With quantum bits superfast computers can be produced, so-called topological quantum computers. This research is part of the new FOM Programme 'Topological Insulators' that has just started.
Reference
Superconductivity in the doped topological insulator CuxBi2Se3 under high pressure,
T.V. Bay1, T. Naka2, Y.K. Huang1, H. Luigjes1, M.S. Golden1 and A. de Visser1
1Institute of Physics, University of Amsterdam, 2National Institute for Materials Science, Tsukuba, Japan.
The article will be available online via: http://prl.aps.org/pdf/PRL/v108/i5/e057001
Contact
For further information please contact (Mr.) Dr. A. (Anne) de Visser (University of Amsterdam), +31 (0)20 525 57 32.