Light touch transforms material into a superconductor
(麻豆淫院Org.com) -- A non-superconducting material has been transformed into a superconductor using light, Oxford University researchers report.
One hundred years after superconductivity was first observed in 1911, the team from Oxford, Germany and Japan observed conclusive signatures of superconductivity after hitting a non-superconductor with a strong burst of laser light.
鈥榃e have used light to turn a normal insulator into a superconductor,鈥� says Professor Andrea Cavalleri of the Department of 麻豆淫院ics at Oxford University and the Max Planck Department for Structural Dynamics, Hamburg. 鈥楾hat鈥檚 already exciting in terms of what it tells us about this class of materials. But the question now is can we take a material to a much higher temperature and make it a superconductor?鈥�
The material the researchers used is closely related to high-temperature copper oxide superconductors, but the arrangement of electrons and atoms normally act to frustrate any electronic current.
In the journal Science, they describe how a strong infrared laser pulse was used to perturb the positions of some of the atoms in the material. The compound, held at a temperature just 20 degrees above absolute zero, almost instantaneously became a superconductor for a fraction of a second, before relaxing back to its normal state.
Superconductivity describes the phenomenon where an electric current is able to travel through a material without any resistance 鈥� the material is a perfect electrical conductor without any energy loss.
High-temperature superconductors can be found among a class of materials made up of layers of copper oxide, and typically superconduct up to a temperature of around 鈥�170掳C. They are complex materials where the right interplay of the atoms and electrons is thought to 鈥榣ine up鈥� the electrons in a state where they collectively move through the material with no resistance.
鈥榃e have shown that the non-superconducting state and the superconducting one are not that different in these materials, in that it takes only a millionth of a millionth of a second to make the electrons 鈥渟ynch up鈥� and superconduct,鈥� says Professor Cavalleri. 鈥楾his must mean that they were essentially already synched in the non-superconductor, but something was preventing them from sliding around with zero resistance. The precisely tuned laser light removes the frustration, unlocking the superconductivity.鈥�
The advance immediately offers a new way to probe with great control how superconductivity arises in this class of materials, a puzzle ever since high-temperature superconductors were first discovered in 1986.
But the researchers are hopeful it could also offer a new route to obtaining superconductivity at higher temperatures. If superconductors that work at room temperature could be achieved, it would open up many more technological applications.
鈥楾here is a school of thought that it should be possible to achieve superconductivity at much higher temperatures, but that some competing type of order in the material gets in the way,鈥� says Professor Cavalleri. 鈥榃e should be able to explore this idea and see if we can disrupt the competing order to reveal superconductivity at higher temperatures. It鈥檚 certainly worth trying!鈥�
Provided by Oxford University
