The press service of the Moscow Institute of Physics and Technology (MIPT), quoting an article in the journal Scientific Reports, said physicists of the Joint Institute for High Temperatures of the Russian Academy of Sciences and the MIPT conducted the experiment – this proved the existence of a intermediate phase between the crystalline and liquid states in a monolayer dusty plasma system.

    There are four forms of matter – liquid, solid, gas and plasma. It was believed that most solid bodies became liquid upon being heated. But several decades ago, physicists Michael Kosterlitz, Duncan Haldane and David Thouless advanced the theory, according to which crystals before being transformed into liquid pass through a special phase – the hexatic phase.

    In 2016, they won the Nobel Prize for physics on the basis of this theory, but no practical proof had been produced. 

    While conducting the experiment, the scientists created a special installation and filled it with argon plasma. Inside, they released spherical polystyrene microparticles covered in a thin nickel film. When heated or cooled, the microparticles moved in the same manner as crystals. The particles were then exposed to laser radiation. 

    Observation showed that the nature of the movement of the particles, when heated or cooled, coincided perfectly with the theory. 

    The Russian scientists intend to continue experiments with plasma, expecting to create new materials as a result of their work.

    “Our experiment was successful due to a number of factors. For example, we used an unconventional approach to form a monolayer dusty system, namely we used particles with a metal surface that are capable of absorbing laser radiation and converting it into the energy of their own motion,” Oleg Petrov, head of the MIPT’s Laboratory for Physics of Active Matter and Systems, was quoted as saying.

    “The particle system had a long time for relaxation before recording the experimental series. In addition, a homogeneous laser beam was used to uniformly influence the structure and its precise heating.”    

Research into physical matter of two-dimensional systems is important in that it will allow for the creation of new materials for micro-electronics, medicine and other applications.