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Separation of orbital contributions to the optical conductivity of BaVS$_3$

I. Kezsmarki·G. Mihaly·R. Gaal·N. Barisic·A. Akrap·H. Berger·L. Forro·C. C. Homes·L. Mihaly
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Abstract

The correlation-driven metal-insulator transition (MIT) of BaVS$_3$ was studied by polarized infrared spectroscopy. In the metallic state two types of electrons coexist at the Fermi energy: The quasi 1D metallic transport of $A_{1g}$ electrons is superimposed on the isotropic hopping conduction of localized $E_g$ electrons. The "bad-metal" character and the weak anisotropy are the consequences of the large effective mass $m_{eff}\approx7m_e$ and scattering rate $Γ\geq160$ meV of the quasi-particles in the $A_{1g}$ band. There is a pseudo-gap above $T_{MI}=69$ K, and in the insulating phase the gap follows the BCS-like temperature dependence of the structural order parameter with $Δ_{ch}\approx42$ meV in the ground state. The MIT is described in terms of a weakly coupled two-band model.

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I. Kezsmarki, G. Mihaly, R. Gaal, N. Barisic, A. Akrap, H. Berger, L. Forro, C. C. Homes, L. Mihaly. 2006-02-13. Separation of orbital contributions to the optical conductivity of BaVS$_3$. https://doi.org/10.1103/physrevlett.96.186402

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