Less than a decade ago, researchers found a peculiar phase of matter where the electrons of a particular compound would behave in two very distinct phases. Some had spins that were very well organized, while others were a complete mess. They called this the “half fire, half ice” state. Now, researchers have found that under some extremely specific conditions, the opposite state forms.
The curious material in which they made this discovery is called Sr3CuIrO6, a magnetic compound of strontium, copper, iridium, and oxygen. In 2016, when studying this material, Alexei Tsvelik and Weiguo Yin from the Brookhaven National Laboratory uncovered a peculiar phase of matter over a certain temperature and under the influence of an external magnetic field.
Electrons have a property called spin, which is akin to the angular momentum, like that of a spinning top. They can point in specific directions or in random ones, but in this state – the “half fire, half ice” – the sites where copper atoms are have spins that are all disordered, while on the iridium sites, the spins are fully ordered.
The team has now discovered that, at a very specific point, the state goes from fire and ice to ice and fire. The copper sites become “frozen”, while the iridium sites become “hot” with randomly pointing spins. In particular, the switch between the two states is very sharp, and the team thinks that this could have some exciting applications.
A graph showing the changes in magnetic field (h) or temperature (T) to get to the peculiar state.
Image Credit: Brookhaven National Laboratory
“Finding new states with exotic physical properties — and being able to understand and control the transitions between those states — are central problems in the fields of condensed matter physics and materials science,” Yin said in a statement. “Solving those problems could lead to great advances in technologies like quantum computing and spintronics.”
“We suggest that our findings may open a new door to understanding and controlling phases and phase transitions in certain materials,” added Tsvelik.
The team believes that intriguing applications could be made in advanced refrigeration technologies, but the sharpness of the phase change could also be used in quantum information technology – for example, as a form of storage. Instead of 0s and 1s, you might have fire/ice or ice/fire.
“Next, we are going to explore the fire-ice phenomenon in systems with quantum spins and with additional lattice, charge, and orbital degrees of freedom,” said Yin. “The door to new possibilities is now wide open.”
The study is published in the journal Physical Review Letters.
