Metal-insulator crossover behavior at the surface of $NiS_2$

Sarma, DD and Krishnakumar, SR and Weschke, E and Schubler-Langeheine, C and Mazumdar, Chandan and Kilian, L and Kaindl, G and Mamiya, K and Fujimori, SI and Fujimori, A and Miyadai, T (2003) Metal-insulator crossover behavior at the surface of $NiS_2$. In: Physical Review B (Condensed Matter and Materials Physics), 67 . pp. 155112-1.

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Abstract

We have performed a detailed high-resolution electron spectroscopic investigation of $NiS_2$ and related Se-substituted compounds, $NiS_{2-x}Se_x$, which are known to be gapped insulators in the bulk at all temperatures. A large spectral weight at the Fermi energy of the room temperature spectrum, in conjunction with the extreme surface sensitivity of the experimental probe, however, suggests that the surface layer is metallic at about 300 K. Interestingly, the evolution of the spectral function with decreasing temperature is characterized by a continuous depletion of the single-particle spectral weight at the Fermi energy and the development of a gap-like structure below a characteristic temperature, providing evidence for a metal-insulator crossover behavior at the surfaces of $NiS_2$ and of related compounds. These results provide a consistent description of the unusual transport properties observed in these systems.

Item Type:	Journal Article
Publication:	Physical Review B (Condensed Matter and Materials Physics)
Publisher:	American Physical Society
Additional Information:	Copyright for this article belongs to American Physical Society (APS).
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	23 May 2006
Last Modified:	19 Sep 2010 04:16
URI:	http://eprints.iisc.ac.in/id/eprint/2052

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