New phase of matter synthesised, could be found in some planet cores

A new study has been published where for the first time, water has been turned into a new phase of matter referred to as superionic ice or superionic water, long enough to be studied.

"It's a new state of matter, so it basically acts as a new material, and it may be different from what we thought," said co-author Vitali B. Prakapenka, a University of Chicago geophysicist and a beamline scientist at the Advanced Photon Source at Argonne National Laboratory.

Also known as ice XVIII, superionic ice is one of the nineteen known crystalline phases of ice. By compacting a water droplet between two diamonds and hitting it with a powerful laser, scientists subjected the droplet to such extreme temperatures and pressures. The water molecules then break apart, allowing the oxygen ions to crystallize and form an evenly spaced lattice through which the hydrogen ions may then float freely. As a result, superionic ice can conduct electricity, with hydrogen ions and electrons migrating towards anodes and cathodes, respectively.

"Imagine a cube, a lattice with oxygen atoms at the corners connected by hydrogen. When it transforms into this new superionic phase, the lattice expands, allowing the hydrogen atoms to migrate around while the oxygen atoms remain steady in their positions. It's kind of like a solid oxygen lattice sitting in an ocean of floating hydrogen atoms," said Prakapenka.

Using a 0.2-carat diamond anvil, researchers pressurized the water droplet to 3.5 million times Earth's atmospheric pressure, and the laser raised its temperature beyond that of the surface of the sun. Using a synchrotron, an electron-accelerating device that generates X-rays, the study team could determine the structure of the superionic ice over its lifespan based on the scattering of the X-rays.

The existence of ions within the structure of this ice can produce magnetic fields, leading researchers to question whether they could find superionic ice in the cores of planets like Neptune or Uranus or frozen moons like Europa. The presence of this ice could assist in the generation of the magnetospheres surrounding these planets or any other similar worlds. Magnetospheres help shield planets from cosmic radiation, making them more habitable; therefore, determining what planets may have superionic ice form could help scientists search for life outside of our solar system.