Structural investigation of the insulator-metal transition in NiS${}_{2-x}$Se${}_x$ compounds

Abstract

We report on a combined measurement of high-resolution x-ray diffraction on powder and Raman scattering on single crystalline NiS2-xSex samples that exhibit the insulator-metal transition with Se doping. Via x-rays, an abrupt change in the bond length between Ni and S (Se) ions was observed at the transition temperature, in sharp contrast to the almost constant bond length between chalcogen ions. Raman scattering, a complementary technique with the unique sensitivity to the vibrations of chalcogen bonds, revealed no anomalies in the phonon spectrum, consistent with the x-ray diffraction results. This indicates the important role of the interaction between Ni and S (Se) in the insulator-metal transition. The potential implication of this interpretation is discussed in terms of current theoretical models.

arXiv comment17 pages, 12 figures, to appear in PRB

References in corpus (8)

• Mott transition in VO2 revealed by infrared spectroscopy and nano-imaging
• A Microscopic View on the Mott transition in Chromium-doped V2O3
• Metal-insulator transition in NiS${}_{2-x}$Se${}_x$
• Magnetic structure, magnetoelastic coupling, and thermal properties of EuCrO${}_3$ nano-powders
• Magnetic Phase Diagram and Metal-Insulator Transition of NiS2-xSex
• Direct observation of the bandwidth control Mott transition in the NiS${}_{2-x}$Se${}_x$ multiband system
• X-ray photoemission study of NiS_{2-x}Se_x (x = 0.0 - 1.2)
• Electronic Structure Change of NiS${}_{2-x}$Se${}_x$ in the Metal-Insulator Transition Probed by X-ray Absorption Spectroscopy

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• Closing of the Mott gap near step edges in NiS2
• Clean realization of the Hund physics near the Mott transition: $\mathrm{Ni}{\mathrm{S}}_2$ under pressure