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arXiv · 0812.3394

Pressure-induced magnetic transition and volume collapse in FeAs superconductors: An orbital-selective Mott scenario

Andreas Hackl·Matthias Vojta
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Abstract

Motivated by pressure experiments on FeAs-122 superconductors, we propose a scenario based on local-moment physics to explain the simultaneous disappearance of magnetism, reduction of the unit cell volume, and decrease in resistivity. In this scenario, the low-pressure magnetic phase derives from Fe moments, which become screened in the paramagnetic high-pressure phase. The quantum phase transition can be described as an orbital-selective Mott transition, which is rendered first order by coupling to the lattice, in analogy to a Kondo volume collapse. Spin-fluctuation driven superconductivity competes with antiferromagnetism and may be stabilized at low temperatures in the high-pressure phase. The ideas are illustrated by a suitable mean-field analysis of an Anderson lattice model.

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Andreas Hackl, Matthias Vojta. 2008-12-18. Pressure-induced magnetic transition and volume collapse in FeAs superconductors: An orbital-selective Mott scenario. https://doi.org/10.1088/1367-2630/11/5/055064

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