Magnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition

TitleMagnetism, structure, and charge correlation at a pressure-induced Mott-Hubbard insulator-metal transition
Publication TypeJournal Article
Year of Publication2011
AuthorsFeng, Y, Jaramillo, R, Banerjee, A, Honig, JM, Rosenbaum, TF
JournalPhysical Review B
Volume83
Issue3
Date Published2011/01/11/
KeywordsAntiferromagnetism, Chalcogenides, Metal-Insulator Transitions, Mott Transition, NiS2, Pressure, X-Ray Scattering
Abstract

We use synchrotron x-ray diffraction and electrical transport under pressure to probe both the magnetism and the structure of single-crystal NiS2 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.

URLhttp://link.aps.org/doi/10.1103/PhysRevB.83.035106
Short TitlePhys. Rev. B