Importance of van der Waals interactions and cation-anion coupling in an organic quantum spin liquid
Abstract
The Mott insulator β'-EtMe3Sb [Pd(dmit)2] 2 belongs to a class of charge transfer solids with highly frustrated triangular lattice of S =1 /2 molecular dimers and a quantum-spin-liquid ground state. Our experimental and ab initio theoretical studies show the fingerprints of strong correlations and disorder, the important role of cation-dimer bonding in charge redistribution, no sign of intra- and interdimer dipoles, and the decisive van der Waals contribution to interdimer interactions and the ground-state structure. The latter consists of quasidegenerate electronic states related to the different configurations of cation moieties, which permit two different equally probable orientations. Upon reducing the temperature, the low-energy excitations slow down, indicating glassy signatures as the cation motion freezes out.
- Publication:
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Physical Review B
- Pub Date:
- June 2018
- DOI:
- 10.1103/PhysRevB.97.245134
- arXiv:
- arXiv:1710.01942
- Bibcode:
- 2018PhRvB..97x5134L
- Keywords:
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- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 5 pages, 6 figures