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Entangled tetrahedron ground state and excitations of the magnetoelectric skyrmion material Cu2OSeO3.

Authors :
Romhányi, Judit
Van den Brink, Jeroen
Rousochatzakis, Ioannis
Source :
Physical Review B: Condensed Matter & Materials Physics. Oct2014, Vol. 90 Issue 14, p140404-1-140404-5. 5p.
Publication Year :
2014

Abstract

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 alsofully 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. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
10980121
Volume :
90
Issue :
14
Database :
Academic Search Index
Journal :
Physical Review B: Condensed Matter & Materials Physics
Publication Type :
Academic Journal
Accession number :
100067190
Full Text :
https://doi.org/10.1103/PhysRevB.90.140404