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Add to Calendar 12/6/2019 1:00 pm 12/6/2019 America/Chicago Condensed Matter Seminar: Low energy electrodynamics of the missing superconducting electrons in overdoped cuprates DESCRIPTION:

Overdoped high-temperature cuprate superconductors have been widely believed to be described by the physics of d-wave BCS-like superconductivity. This view was strongly challenged by recent measurements of the superfluid density which found that even as the carrier concentration increases on the overdoped side, the superfluid density decreases – Cooper pairs seem to be ‘missing’ from the condensate. In this talk, I will discuss how we use time-domain THz spectroscopy combined with kHz range mutual inductance measurements on overdoped La2-xSrxCuO4 to directly locate the ‘missing’ carriers and discover that they display an exceedingly large metal-like response even deep into the superconducting state. I will discuss various explanations/consequences for this behavior including quantum phase fluctuations as the critical doping is approached. I will also present some recent results using non-linear THz spectroscopy that potentially highlight an anomalously large third-order susceptibility above the superconducting Tc. These results challenge the conventional view of describing the normal state of overdoped cuprates as a weakly interacting Fermi liquid.

 

\n\nSPEAKER: Fahad Mahmood, University of Illinois at Urbana-Champaign
190 ESB false

Condensed Matter Seminar: Low energy electrodynamics of the missing superconducting electrons in overdoped cuprates

Speaker Fahad Mahmood, University of Illinois at Urbana-Champaign
Date: 12/6/2019
Time: 1 p.m.
Location: 190 ESB
Sponsor: Physics - Condensed Matter
Event Type: Seminar/Symposium
 

Overdoped high-temperature cuprate superconductors have been widely believed to be described by the physics of d-wave BCS-like superconductivity. This view was strongly challenged by recent measurements of the superfluid density which found that even as the carrier concentration increases on the overdoped side, the superfluid density decreases – Cooper pairs seem to be ‘missing’ from the condensate. In this talk, I will discuss how we use time-domain THz spectroscopy combined with kHz range mutual inductance measurements on overdoped La2-xSrxCuO4 to directly locate the ‘missing’ carriers and discover that they display an exceedingly large metal-like response even deep into the superconducting state. I will discuss various explanations/consequences for this behavior including quantum phase fluctuations as the critical doping is approached. I will also present some recent results using non-linear THz spectroscopy that potentially highlight an anomalously large third-order susceptibility above the superconducting Tc. These results challenge the conventional view of describing the normal state of overdoped cuprates as a weakly interacting Fermi liquid.

 

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