Ultralow-dissipative conductivity by Dirac fermions in BaFe${}_2$As${}_2$

Abstract

We report on the anomalous behavior of the complex conductivity of BaFe${}_2$As${}_2$, which is related to the Dirac cone, in the terahertz (THz)-frequency region. Above the spin-density-wave (SDW) transition temperature, the conductivity spectra follow the Drude model. In the SDW state, the imaginary part of the complex conductivity, ${\sigma }_2$, is suppressed in comparison to that expected according to the Drude model. The real part, ${\sigma }_1$, exhibits nearly Drude-like behavior. This behavior (i.e., almost no changes in ${\sigma }_1$ and the depression of ${\sigma }_2$) can be regarded as the addition of extra conductivity without any dissipations in the Drude-type conductivity. The origin of this ultralow-dissipative conductivity is found to be due to conductivity contribution from quasiparticles within the Dirac cone. In other words, we are able to observe the dynamics of Dirac fermions through the conductivity spectra of BaFe${}_2$As${}_2$, clearly and directly.

5pages, 3 figures

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Cited by in corpus (5)

• Two-dimensional Massless Dirac Fermions in Antiferromagnetic AFe2As2 (A = Ba, Sr)
• Synthetic non-Abelian gauge fields and gravitomagnetic effects in tilted Dirac cone systems
• Mobility spectrum analytical approach for intrinsic band picture of Ba(FeAs)${}_2$
• Emergence of the minority hole with high mobility on the electrical transport in the Fe-pnictides Ba(Fe${}_{1-x}$Mn${}_x$As)${}_2$
• Linear scaling relation between two-dimensional massless Dirac fermion Fermi velocity and Fe-As bond length in iron arsenide superconductor systems