Structural instability in polyacene: A projector quantum Monte Carlo study

Srinivasan, Bhargavi and Ramasesha, S (1998) Structural instability in polyacene: A projector quantum Monte Carlo study. In: Physical Review B, 57 (15). pp. 8927-8933.

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Abstract

We have studied polyacene within the Hubbard model to explore the effect of electron correlations on the Peierls’ instability in a system marginally away from one dimension. We employ the projector quantum Monte Carlo method to obtain ground-state estimates of the energy and various correlation functions. We find strong similarities between polyacene and polyacetylene which can be rationalized from the real-space valence-bond arguments of Mazumdar and Dixit. Electron correlations tend to enhance the Peierls’ instability in polyacene. This enhancement appears to attain a maximum at $U/t\sim3.0$, and the maximum shifts to larger values when the alternation parameter is increased. The system shows no tendency to destroy the imposed bond-alternation pattern, as evidenced by the bond-bond correlations. The cis distortion is seen to be favored over the trans distortion. The spin-spin correlations show that undistorted polyacene is susceptible to a spin-density-wave distortion for large interaction strength. The charge-charge correlations indicate the absence of a charge-density-wave distortion for the parameters studied.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	APS
Additional Information:	Copyright of this article belongs to APS.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	16 Jan 2007
Last Modified:	19 Sep 2010 04:34
URI:	http://eprints.iisc.ac.in/id/eprint/9512

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