Department of Physics, Engineering Physics & Astronomy

Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

Superconductivity and Giant Fluctuations in Quantum Critical Metals

Stephen Julian
University Of Toronto

Wednesday, December 1, 2004
10:30 AM @ Stirling 501

Abstract:

I will review experimental work on magnetic metals to which hydrostatic pressure has been applied in order to suppress the magnetic ordering transition to absolute zero. At such 'quantum critical points', superconductivity seems to appear regularly in the millikelvin temperature regime, with Cooper pairing presumably mediated by magnetic fluctuations. The normal state of these metals is very strange too, with quasiparticles moving diffusively, showing stronger scattering than is expected from simple magnetic fluctuation models. In some systems it seems possible that giant, very slow fluctuations mimic the effects of static disorder. In CeCoIn$_5$, which seems to exist at a quantum critical point at ambient pressure, we have evidence from quantum oscillation measurements of a breakdown of Fermi liquid theory in the low millikelvin temperature range.