Magnetoelastic coupling and spin excitations in the spin-gap system (VO)(2)P2O7: A Raman scattering study

Article

关键词: HEISENBERG-ANTIFERROMAGNET;    MAGNETIC EXCITATIONS;    LIGHT-SCATTERING;    PEIERLS SYSTEMS;    CUGEO3;    CHAIN;    SUSCEPTIBILITY;    FLUCTUATIONS;    SPECTRUM;    LADDER;   

DOI  :  10.1103/PhysRevB.61.6126

来源: SCIE

【 摘 要 】

Single crystals of the spin-gap system (VO)(2)P2O7 have been investigated by means of Raman scattering. At temperatures below T = 75 K approximate to 2 Delta(01)(k = 0), with Delta(01) the singlet-triplet gap, a shoulder appears at 47 cm(-1). An analysis of the polarization selection rules and the temperature dependence of the scattering intensity leads to its identification as a singlet bound state with very small binding energy. Therefore in contrast to recent theoretical models the importance of frustration for this compound must be rejected. The observation of a strong anharmonicity of three phonons with energies close to Delta(01) at the zone boundary and additional quasielastic light scattering, however, both point to a strong spin-phonon coupling in this system. We propose this coupling to be the origin of the second bound triplet state observed in recent neutron-scattering experiments.

【 授权许可】

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