Entangled tetrahedron ground state and excitations of the magneto-electric skyrmion material Cu${}_2$OSeO${}_3$

Abstract

The strongly correlated cuprate Cu${}_2$OSeO${}_3$ has recently been identified as the first insulating system exhibiting a skyrmion lattice phase. Using a microscopic multi-boson theory for its magnetic ground state and excitations, we establish the presence of two distinct types of modes: a low energy manifold that includes a gapless Goldstone mode and a set of weakly dispersive high-energy magnons. These spectral features are the most direct signatures of the fact that the essential magnetic building blocks of Cu${}_2$OSeO${}_3$ are not individual Cu spins, but rather weakly-coupled Cu${}_4$ tetrahedra. Several of the calculated excitation energies are in nearly perfect agreement with reported Raman and far-infrared absorption data, while the magneto-electric effect determined within the present quantum-mechanical framework is also fully consistent with experiments, giving strong evidence in the entangled Cu${}_4$ tetrahedra picture of Cu${}_2$OSeO${}_3$. The predicted dispersions along with the dynamical dipole and quadrupole spin structure factors call for further experimental tests of this picture.

4 pages main text + 5 pages supplementary material, 3 figures

References in corpus (7)

• Spontaneous Skyrmion Ground States in Magnetic Metals
• Strong Dzyaloshinskii-Moriya Interaction and Origin of Ferroelectricity in Cu2OSeO3
• The quantum origins of skyrmions and half-skyrmions in Cu2OSeO3
• Driven skyrmions and dynamical transitions in chiral magnets
• Ferrimagnetism of the magnetoelectric compound Cu${}_2$OSeO${}_3$ probed by ${}^{77}$Se NMR
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• Establishing the fundamental magnetic interactions in the chiral skyrmionic Mott insulator Cu2OSeO3 by terahertz electron spin resonance

Cited by in corpus (22)

• Collective spin excitations of helices and magnetic skyrmions: review and perspectives of magnonics in non-centrosymmetric magnets
• The quantum origins of skyrmions and half-skyrmions in Cu2OSeO3
• New magnetic phase of the chiral skyrmion material Cu2OSeO3
• Dynamical magnetoelectric phenomena of multiferroic skyrmions
• Increased lifetime of metastable skyrmions by doping
• Magnon spectrum of the helimagnetic insulator Cu2OSeO3
• Magnetic structure and excitation spectrum of the hyperhoneycomb Kitaev magnet $\beta$-Li${}_2$IrO${}_3$
• Ballistic magnon heat conduction and possible Poiseuille flow in the helimagnetic insulator Cu${}_2$OSeO${}_3$
• Magnonic Weyl states in Cu2OSeO3
• Measuring the Formation Energy Barrier of Skyrmions in Zinc Substituted Cu${}_2$OSeO${}_3$
• A tunable time-resolved spontaneous Raman spectroscopy setup for probing ultrafast collective excitation and quasiparticle dynamics in quantum materials
• Spin excitations in the skymion host Cu2OSeO3
• Megahertz dynamics in skyrmion systems probed with muon-spin relaxation
• Low energy magnons in the chiral ferrimagnet ${\text{Cu}}_2{\text{OSeO}}_3$: a coarse-grained approach
• Low energy magnon dynamics and magneto-optics of the skyrmionic Mott insulator Cu${}_2$OSeO${}_3$
• Hierarchical excitations from correlated spin tetrahedra on the breathing pyrochlore lattice
• Site-specific electronic and magnetic excitations of the skyrmion material Cu${}_2$OSeO${}_3$
• Tuning the structure of Skyrmion lattice system Cu2OSeO3 under pressure
• Inelastic light scattering in the spin cluster Mott insulator Cu${}_2$OSeO${}_3$
• Coupled dynamics of long-range and internal spin cluster order in Cu${}_2$OSeO${}_3$
• Quintuplet condensation in the skyrmionic insulator Cu2OSeO3 at ultrahigh magnetic fields
• Seeded Chemical Vapor Transport Growth of Cu${}_2$OSeO${}_3$