Discovering and controlling exotic physical states is key in condensed matter physics and materials science. It has the potential to drive advancements in quantum computing and spintronics.
While studying a ferrimagnet model, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory uncovered a new phase of matter called “half-ice, half-fire.” This state is a twin to the “half-fire, half-ice” phase discovered in 2016.
This newly discovered phase, called “half ice, half fire,” features a unique arrangement of electron spins—some highly ordered (“cold”) and others highly disordered (“hot”). This distinctive pattern allows for extremely sharp phase transitions at moderate temperatures, showing promise for applications in energy and information technology.
In 2016, while examining the magnetic compound Sr3CuIrO6, researchers uncovered the “half-fire, half-ice” phase. This state emerged under a specific external magnetic field.
It revealed a striking spin pattern: the “hot” spins at copper sites were fully disordered with smaller magnetic moments. In contrast, the “cold” spins at iridium sites were fully ordered, carrying larger magnetic moments. It showcased a unique interplay of magnetic properties across the atomic lattice.
Despite extensive research, the practical application of the “half-fire, half-ice” state remained unclear, as the one-dimensional Ising model—responsible for producing this state—does not allow a finite-temperature phase transition.
Exotic matter-wave states revealed in condensed matter physics
Researchers recently reported a breakthrough in two publications, suggesting that this “forbidden” phase transition could be accessed through ultranarrow phase crossovers at fixed finite temperatures in systems with and without external magnetic fields.
Researchers found that “half fire, half ice” has a hidden twin state, “half ice, half fire,” where hot and cold spins switch roles. Phase transitions occur over an ultranarrow temperature range, opening possibilities for future technologies.
These include refrigeration systems using ultrasharp phase switching with giant magnetic entropy changes and quantum information storage, where the phases act as data bits.
Researchers’ next aim is to explore the fire-ice phenomenon in systems with quantum spins and additional lattice, charge, and orbital degrees of freedom.
Journal References:
Weiguo Yin and A. M. Tsvelik. Phase Switch Driven by the Hidden Half-Ice, Half-Fire State in a Ferrimagnet. Physical Review Letters. DOI: 10.1103/PhysRevLett.133.266701
Weiguo Yin, Christopher R. Roth, and Alexei M. Tsvelik. Spin frustration and an exotic critical point in ferromagnets from nonuniform opposite 𝑔 factors. Physical Review B. DOI: 10.1103/PhysRevB.109.054427