About
Already in the early days of cuprate high Tc superconductivity it was noticed that the metallic state in the best superconductors is highly anomalous, being called “strange metal”. A hallmark is the linear-in-temperature resistivity, all the way from the superconducting Tc up to the melting point of the crystal while it also became clear that for instance the magneto transport is highly unusual. A variety of other systems were identified showing similar behaviors and in the course of time the idea that this is rooted in a quantum phase transition (QPT) became popular revolving around the anomalous damping of the Fermi-liquid quasiparticles by the critical fluctuations: the “Marginal Fermi liquid” idea. Spurred by theoretical advances such as the holographic duality the study of strange metals in especially the cuprates became recently again a hot topic. It was discovered that the linear resistivity reflects the “Planckian dissipation”-- the fact that the current lifetime τ_ℏ≈ℏ⁄k_B T, while evidences appeared that the strange metals behave like phases of matter, while contrary to earlier believes also the metals in overdoped cuprates are strange. The different theoretical views will be highlighted followed by an account of the recent experimental progress.
Topics
- Theory: the Hertz-Millis type description of a Fermi-liquid coupled to a quantum critical state versus the holographic description of a densely many body entangled metallic phase of matter.
- Experiment: transport measurements and other macroscopic properties in various strange metal systems and an account of what the various spectroscopic methods reveal (ARPES, STS, RIXS, EELS).
Instructors
- Subir Sachdev, Harvard
- Andrey Chubukov, University of Minnesota
- Nigel Hussey, University of Bristol and HFML, Nijmegen
- Z.X. Shen, Stanford University
Who Can Attend?
Graduate students, post-docs, and other scientists interested in learning about the recent developments in the study of strange metals as observed in cuprate superconductors and related systems. The tutorial talks will be very pedagogical, highlighting the present state of this mystery story. Does it originate in the quantum critical fluctuations associated with a quantum phase transition giving rise to an anomalous damping of quasiparticles, or is it revealing the densely many body entangled metallic phases predicted by the string theoretical AdS/CFT correspondence? Both these theoretical ideas and the very recent experimental progress both in transport and spectroscopy will be highlighted.