DOE OSTI · 2935903
Phase diagram and spectroscopic signatures of a supersolid in the quantum ising magnet K 2 Co(SeO 3 ) 2
Abstract
Supersolid phases are quantum-entangled states of matter exhibiting the dual characteristics of superfluidity and solidity. Theory predicts that hard-core bosons on a triangular lattice can form such phases at half filling and near complete filling. Leveraging an exact mapping between bosons and spin-$\frac{1}{2}$ degrees of freedom, here we show that these phases are realized in the triangular-lattice antiferromagnet K 2 Co(SeO 3 ) 2 . At zero field, neutron diffraction reveals the development of quasi-two-dimensional $\sqrt3$ x $\sqrt3$ magnetic order with Z 3 translational symmetry breaking (solidity), though with reduced amplitude indicating strong quantum fluctuations. These fluctuations manifest as equidistant bands of continuum neutron scattering, where the lowest-energy mode is gapless at K ($\frac{1}{3}$ $\frac{1}{3}$), consistent with broken U(1) spin rotational symmetry (superfluidity). For c-axis-oriented magnetic fields near saturation, we find a second phase consistent with a high-field supersolid. These two supersolids are separated by a pronounced 1/3 magnetization plateau phase that supports coherent spin waves, from which we determine the underlying spin Hamiltonian.
Explore related subjects
Keep this discovery
Chen, Tong [Johns Hopkins University, Baltimore, MD (United States)] (ORCID:0000000179945717), Ghasemi, Alireza [Johns Hopkins University, Baltimore, MD (United States)], Zhang, Junyi [Johns Hopkins University, Baltimore, MD (United States)] (ORCID:0000000333061654), Shi, Liyu [Johns Hopkins University, Baltimore, MD (United States)], Tagay, Zhenisbek [Johns Hopkins University, Baltimore, MD (United States)], Chen, Youzhe [Johns Hopkins University, Baltimore, MD (United States)], Chen, Lei [Rice University, Houston, TX (United States)] (ORCID:0000000212825144), Choi, Eun Sang [Florida State University, Tallahassee, FL (United States)], Jaime, Marcelo [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000153605220), Lee, Minseong [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000223699913), Hao, Yiqing [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000157213224), Cao, Huibo [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000259704980), Winn, Barry L. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000163834318), Podlesnyak, Andrey A. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000193666319), Pajerowski, Daniel M. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000338902379), Zhong, Ruidan [Shanghai Jiao Tong University (China); Princeton University, NJ (United States)], Xu, Xianghan [Princeton University, NJ (United States)] (ORCID:000000016854300X), Armitage, N. P. [Johns Hopkins University, Baltimore, MD (United States)] (ORCID:0000000175682059), Cava, Robert [Princeton University, NJ (United States)], Broholm, Collin [Johns Hopkins University, Baltimore, MD (United States); NIST Center for Neutron Research, Gaithersburg, MD (United States)] (ORCID:0000000215699892). 2026-02-18. Phase diagram and spectroscopic signatures of a supersolid in the quantum ising magnet K 2 Co(SeO 3 ) 2. https://doi.org/10.1038/s41467-026-69661-0
Cite the original work for its findings. Save a collection to share your selection of sources.
Discover connections
Connections use source metadata and explicit phrase matches, not verified experimental comparisons.