Abstract
The electronic structure of a quantum spin liquid compound, , has been studied with angle-resolved photoemission spectroscopy, together with two other salts in the valence bond solid or antiferromagnetic state. , being a Mott insulator, has its lower Hubbard band identified, with a soft energy gap at the chemical potential. In addition, the spectral features exhibit anomalously broad linewidth and negligible dispersion, which fit well to the calculated energy levels of an isolated dimer. We suggest that these electronic characteristics might be the manifestation of the spin-charge separation in a two-dimensional quantum spin liquid.
- Received 2 March 2013
- Revised 18 January 2014
DOI:https://doi.org/10.1103/PhysRevB.89.075105
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