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arXiv · 0910.2359

Metal-insulator quantum critical point beneath the high Tc superconducting dome

Suchitra E. Sebastian·N. Harrison·M. M. Altarawneh·C. H. Mielke·Ruixing Liang·D. A. Bonn·W. N. Hardy·G. G. Lonzarich
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Abstract

An enduring question in correlated systems concerns whether superconductivity is favoured at a quantum critical point (QCP) characterised by a divergent quasiparticle effective mass. Despite such a scenario being widely postulated in high Tc cuprates and invoked to explain non-Fermi liquid transport signatures, experimental evidence is lacking for a critical divergence under the superconducting dome. We use ultra-strong magnetic fields to measure quantum oscillations in underdoped YBa2Cu3O6+x, revealing a dramatic doping-dependent upturn in quasiparticle effective mass at a critical metal-insulator transition beneath the superconducting dome. Given the location of this QCP under a plateau in Tc in addition to a postulated QCP at optimal doping, we discuss the intriguing possibility of two intersecting superconducting subdomes, each centred at a critical Fermi surface instability.

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Suchitra E. Sebastian, N. Harrison, M. M. Altarawneh, C. H. Mielke, Ruixing Liang, D. A. Bonn, W. N. Hardy, G. G. Lonzarich. 2009-10-13. Metal-insulator quantum critical point beneath the high Tc superconducting dome. https://doi.org/10.1073/pnas.0913711107

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