Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition
- X-Ray Science Division
We use synchrotron x-ray diffraction and electrical transport under pressure to probe both the magnetism and the structure of single-crystal NiS{sub 2} across its Mott-Hubbard transition. In the insulator, the low-temperature antiferromagnetic order results from superexchange among correlated electrons and couples to a (1/2, 1/2, 1/2) superlattice distortion. Applying pressure suppresses the insulating state, but enhances the magnetism as the superexchange increases with decreasing lattice constant. By comparing our results under pressure to previous studies of doped crystals, we show that this dependence of the magnetism on the lattice constant is consistent for both band broadening and band filling. In the high-pressure metallic phase the lattice symmetry is reduced from cubic to monoclinic, pointing to the primary influence of charge correlations at the transition. There exists a wide regime of phase separation that may be a general characteristic of correlated quantum matter.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- DOE Contract Number:
- DE-AC02-06CH11357
- OSTI ID:
- 1039514
- Report Number(s):
- ANL/XSD/JA-66847; TRN: US201209%%461
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 83, Issue 3; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- ENGLISH
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