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arXiv · 0711.1066

Role of Interlayer Electron Hopping for Spin Density Wave State in the Zero-Gap Organic Conductor

Shinya Katayama·Akito Kobayashi·Yoshikazu Suzumura
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Abstract

We investigate the formation of density waves in the zero-gap state (ZGS) which has been found in the quasi-two-dimensional organic conductor $α$-(BEDT-TTF)$_2$I$_3$ salt under the hydrostatic pressure. The ZGS exhibits the cone-like dispersion for both the conduction band and the valence band which degenerate each other at the two-dimensional wave vectors, $\pm\mib{k}_0$ forming a zero gap. By using the extended Hubbard model with repulsive interaction we calculate the onset temperature of the spin density wave (SDW) as a function of the interlayer electron hopping, which by itself does not break the cone-like dispersion. It is shown that the SDW with wave number $2\mib{k}_0$ is induced by the combined effect of the interaction, the inter-band excitation across the zero-gap and the interlayer hopping.

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Shinya Katayama, Akito Kobayashi, Yoshikazu Suzumura. 2007-11-07. Role of Interlayer Electron Hopping for Spin Density Wave State in the Zero-Gap Organic Conductor. https://doi.org/10.1143/jpsj.77.014710

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