Electronic Phase Diagram of Cuprate Superconductors – a Balancing Act

Wel​come to a seminar with Zhi-Xun Shen, Depts Physics and Applied Physics, Stanford University, Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory




​Abstract:
High-temperature superconductivity in copper-based materials, with critical temperature well above what was anticipated by the BCS theory, remains a major unsolved physics problem more than 30 years after its discovery. The problem is fascinating because it is simultaneously simple - being a single band and ½ spin system, yet extremely rich - boasting d-wave superconductivity, pseudogap, spin and charge orders, and strange metal phenomenology. For this reason, cuprates emerge as the most important model system for correlated electrons – stimulating conversations on the physics of the Hubbard model, quantum critical points, Planckian metals and other topics. 
At the heart of this challenge is the complex electronic phase diagram consisting of intertwined states with unusual properties. Angle-resolved photoemission spectroscopy has emerged as the leading experimental tool to understand the electronic structure of these states and their relationships [1,2]. In this talk, I will describe our results on band structures and Fermi surfaces [3,4]; the d-wave superconducting state [5,6]; the birth of a metal from a Mott insulator [7-11]; the two energy scales of the pseudogap [8,9,12-13]; the temperature, doping and symmetry properties of the low energy pseudogap and its competition with superconductivity [14-18]; the missing quasiparticle and propensity to order [19-21], the interplay of electron-electron and electron-phonon interactions and the enhanced superconductivity [21-24], the incoherent metal sharply bounded by a critical doping [25-26], and the ubiquitous superconducting phase fluctuations [27,28]. The rich phenomenology suggests that a delicate balance between local Coulomb interaction and electron-phonon interaction holds the key to emerging physics in cuprates – unconventional superconductivity, anomalous metal, novel insulator, and intertwined orders.

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Category Seminar
Location: Kollektorn, lecture room, Kemivägen 9, MC2-huset
Starts: 03 June, 2022, 10:00
Ends: 03 June, 2022, 11:00

Page manager Published: Wed 18 May 2022.