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arXiv · 1212.5719

Enhancement of the London penetration depth in pnictides at the onset of SDW order under superconducting dome

A. Levchenko·M. G. Vavilov·M. Khodas·A. V. Chubukov
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Abstract

Recent measurements of the doping dependence of the London penetration depth \lambda(x) at low temperatures in clean samples of isovalent BaFe_2[As_(1-x)P_x]_2 at T<<Tc [Hashimoto et al., Science 336, 1554 (2012)] revealed a peak in \lambda(x) near optimal doping x=0.3. The observation of the peak at T<<Tc, points to the existence of the quantum critical point (QCP) beneath the superconducting dome. We associate such a QCP with the onset of a spin- density-wave order and show that the renormalization of \lambda(x) by critical magnetic fluctuations, gives rise to the observed feature. We argue that the case of pnictides is conceptually different from a one-component Galilean invariant Fermi liquid, for which correlation effects do not cause the renormalization of the London penetration depth at T=0.

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A. Levchenko, M. G. Vavilov, M. Khodas, A. V. Chubukov. 2012-12-22. Enhancement of the London penetration depth in pnictides at the onset of SDW order under superconducting dome. https://doi.org/10.1103/physrevlett.110.177003

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