SPAIN – An international research team conducted by Eugenio Coronado (Institute for Molecular Science of the Universitat de València- ICMol) has shown that it is possible to maintain superconductivity in two-dimensional limit, one of the most debated questions by solid state physics. This discovery allows to move forward in knowledge of superconductivity properties of materials and opens a way to the miniaturisation of ultrasensitive detectors of magnetic fields.

The work has just been published by Nature Communications. Superconductivity is one of the most fascinating quantum phenomenon of physics. In superconductor state materials conduct electricity without energy loss, which makes them interesting to numerous applications which include the production of most powerful magnets known, ultrasensitive detectors of magnetic fields, efficient electricity conducting and transports without friction (trains which levitate).

Since its discovery in 1911, one of the questions that have intrigued scientists is if it possible that the superconductor state continues when dimensionality of material is reduced from two to three dimension. Intuitively we might think that superconductor state is more difficult to stabilize when the dimensionality decreases.

With graphene isolation -the first two-dimensional material formed by a carbon atoms layer- this question has acquired a great importance. However and despite the extraordinary mechanic, electric and magnetic properties of graphene, superconductivity remains elusive property for this two-dimensional material.

Researchers of the Institute for Molecular Science of the Universitat de València, in the Science Park, conducted by the full university professor of Inorganic Chemistry Eugenio Coronado (ICMol) have shown that superconductivity can remain in two-dimensional limit. Researchers have studied laminating materials which are analogous to graphene but they turn into superconductors in low temperatures. In detail, they have studied electric properties of a wide family of laminating materials called metal dichalcogenides.

The same of graphene, these materials are formed by individual atomic layers which can be easily exfoliated, which allows to obtain laminates with different thickness formed by a specific number of atomic layers. In one of the compounds of this family -tantalum disulphide, TaS2- these researchers have found that, counter to expectations, the temperature in which laminating material convert into superconductor increases when the number of layer decreases, so this property remains in 2D limit. This discovery allows them to go deeply in the knowledge of superconductor properties of materials, lots of them are evasive to scientific community. It opens a way to the development of ultrasensitive detectors of smallest and most efficient  magnetic fields.

This work is the result of a collaboration between the group of Eugenio Coronado, the experimental group of Herre Van der Zant of the Delft University of Technology and the theory group of Francisco Guinea of the IMDEA Nanoscience Institute.

Source: The University of Valencia Science Park (PCUV); http://pcuv.es/en/news-room/noticias-destacadas/2016/superconductividad