Bose–Einstein condensation of a two-magnon bound state in a spin-1 triangular lattice
Source abstract
Abstract
In ordered magnets, the elementary excitations are spin waves (magnons), which obey Bose-Einstein statistics. Similarly to Cooper pairs in superconductors, magnons can be paired into bound states under attractive interactions. The Zeeman coupling to a magnetic field is able to tune the particle density through a quantum critical point, beyond which a 'hidden order' is predicted to exist. Here we report direct observation of the Bose-Einstein condensation of the two-magnon bound state in Na2BaNi(PO4)2. Comprehensive thermodynamic measurements confirmed the two-dimensional Bose-Einstein condensation quantum critical point at the saturation field. Inelastic neutron scattering experiments were performed to establish the microscopic model. An exact solution revealed stable two-magnon bound states that were further confirmed by electron spin resonance and nuclear magnetic resonance experiments, demonstrating that the quantum critical point is due to the pair condensation, and the phase below the saturation field is likely the long-sought-after spin nematic phase.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Quantum, superfluid, helium dynamics · Physics of Superconductivity and Magnetism · Cold Atom Physics and Bose-Einstein Condensates
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (59)
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