TY - JOUR
T1 - Entangled tetrahedron ground state and excitations of the magnetoelectric skyrmion material Cu2OSeO3
AU - Romhányi, Judit
AU - Van Den Brink, Jeroen
AU - Rousochatzakis, Ioannis
N1 - Publisher Copyright:
© 2014 American Physical Society.
PY - 2014/10/29
Y1 - 2014/10/29
N2 - The strongly correlated cuprate Cu2OSeO3 has been recently identified as the first insulating system exhibiting a skyrmion lattice phase. Using a microscopic multiboson 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 Cu2OSeO3 are not individual Cu spins, but rather weakly coupled Cu4 tetrahedra. Several of the calculated excitation energies are in excellent agreement with terahertz electron spin resonance, Raman, and far-infrared experiments, while the magnetoelectric effect determined within the present quantum-mechanical framework is also fully consistent with experiments, giving strong evidence in the entangled Cu4 tetrahedra picture of Cu2OSeO3. The predicted energy and momentum dependence of the dipole and quadrupole spin structure factors call for further experimental tests of this picture.
AB - The strongly correlated cuprate Cu2OSeO3 has been recently identified as the first insulating system exhibiting a skyrmion lattice phase. Using a microscopic multiboson 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 Cu2OSeO3 are not individual Cu spins, but rather weakly coupled Cu4 tetrahedra. Several of the calculated excitation energies are in excellent agreement with terahertz electron spin resonance, Raman, and far-infrared experiments, while the magnetoelectric effect determined within the present quantum-mechanical framework is also fully consistent with experiments, giving strong evidence in the entangled Cu4 tetrahedra picture of Cu2OSeO3. The predicted energy and momentum dependence of the dipole and quadrupole spin structure factors call for further experimental tests of this picture.
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U2 - 10.1103/PhysRevB.90.140404
DO - 10.1103/PhysRevB.90.140404
M3 - Article
AN - SCOPUS:84912050535
VL - 90
JO - Physical Review B
JF - Physical Review B
SN - 2469-9950
IS - 14
M1 - 140404
ER -