Antiferromagnetic dichroism and Davydov splitting of 3d-excitons in a complex multisublattice magnetoelectric CuB2O4

Abstract

The space and time symmetry breaking at magnetic phase transitions in multiferroics results in a number of strongly pronounced optical effects. Our high-resolution spectroscopic study of 3d- excitons in a complex multi-sublattice magnetoelectric CuB2O4 demonstrates that, among those, a large antiferromagnetic linear dichroism is observed which is highly sublattice-sensitive to subtle changes in the spin subsystems. We prove that the discovered linear dichroism is related microscopically to the magnetic Davydov splitting of the exciton states. We announce a novel magnetic phase transition and argue that an elliptical spiral structure rather than a simple circular helix is realized in the incommensurate phase, these findings being overlooked in previous studies by optical and other techniques. We claim that this spectroscopic method can be effectively applied to other materials for revealing hidden features of magnetic structures and phase transitions.

arXiv comment5 pages, 4 figures

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Cited by in corpus (5)

• Nonreciprocal second harmonic generation in a magnetoelectric material
• Lattice dynamics and a magnetic-structural phase transition in the nickel orthoborate $N{i}_3(B{O}_3{)}_2$
• Excitation of multiple phonon modes in copper metaborate CuB${}_2$O${}_4$ via non-resonant impulsive stimulated Raman scattering
• Zeeman and Davydov splitting of Frenkel excitons in the antiferromagnet CuB${}_2$O${}_4$
• Lattice dynamics and electronic transitions in a structurally-complex layered copper borate Cu${}_3$(BO${}_3$)${}_2$