Direct observation of the Haldane gap in NENP by far-infrared spectroscopy in high magnetic fields

23 December 1991

journal article
research article
Published by American Physical Society (APS) in Physical Review Letters

Vol. 67 (26) , 3716-3719
https://doi.org/10.1103/physrevlett.67.3716

Abstract

We report the first direct and comprehensive determination of the energy levels involved in the Haldane gap occurrence: the singlet ground state and the first triplet excited state. Precise values of the parameters are obtained from the analysis of the magneto-optical resonance transitions observed in the far infrared for frequencies ranging from 70 to 1000 GHz and magnetic fields up to 18 T.

Keywords

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