Order-disorder and electronic transitions in $Ag_{2+\delta} S$ single crystals studied by photoemission spectroscopy

Barman, SR and Shanthi, N and Shukla, AK and Sarma, DD (1996) Order-disorder and electronic transitions in $Ag_{2+\delta} S$ single crystals studied by photoemission spectroscopy. In: Physical Review B, 53 (7). pp. 3746-3751.

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Abstract

The electronic structure of $Ag_{2+\delta}s$single crystals is investigated as a function of temperature and nonstoichiometry, $\delta$. It is shown that the stoichiometric, low-temperature $\alpha-Ag_2S$ phase is a band insulator with correlation effects further increasing the band gap. The results suggest that the metal-insulator transition observed with increase in $\delta$ from the stoichiometric $(\delta=0)$ phase in the high-temperature $\beta-Ag_{2+\delta}s$is due to the tuning of the Fermi energy through the mobility edge. The increase in conductivity associated with the insulator-to-insulator transition across the $\alpha-\beta$ phase transformation in the stoichiometric $Ag_2S$ is suggested to arise from the order-disorder transition and the consequent redistribution of states near the top of the valence band.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	American Physical Society
Additional Information:	Copyright of this article belongs to American Physical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	13 Dec 2006
Last Modified:	19 Sep 2010 04:33
URI:	http://eprints.iisc.ac.in/id/eprint/9137

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