German physicists find new exotic state of matter
New Delhi : Physicists from Germany have found evidences of a new exotic state of matter where the constituent particles pair up when limited to two dimensions.
The findings about new state of matter have been published in the journal 'Science' which most likely includes important clues to the intriguing phenomena of superconductivity, said the researchers.
Superconductors are materials through which electricity can flow without any resistance once they are cooled below a certain critical temperature. The physicists performed the experiments in which they confined the gas of ultracold atoms in a 2D medium, they witnessed a unique type of particle pairing which they created using focused laser beams.
Puneet Murthy, a PhD student at Heidelberg University’s Center for Quantum Dynamics said, “In solid-state materials like copper oxides, there are many different effects and impurities that make these materials difficult to study. That is why we use ultracold atoms to simulate the behaviour of electrons in solids. This allows us to create very clean samples and gives us full control over the essential system parameters.”
The technologically most relevant class of materials, with exceptionally high critical temperatures for superconductivity, is poorly understood so far. However, there is evidence that in order for superconductivity to occur, a certain type of particles – the fermions – must pair up.
Also, the research has shown that the materials which become superconducting at relatively high temperatures have layered structures. Selim Jochim, professor at Heidelberg University said, “This means that electrons in these systems can only move in two-dimensional planes.”
He further said, “What we did not understand until now was how the interplay of pairing and dimensionality can lead to higher critical temperatures.” The researchers measured the response of the atoms to a radio-wave pulse using a technique known as radio-frequency spectroscopy.