Patrick A. Lee, Naoto Nagaosa, and Xiao-Gang Wen. “Doping a Mott insulator: Physics of high-temperature superconductivity.” Reviews of Modern Physics 78, no. 1 (2006): 17.

Superconductivity: Cuprates

The discovery of high-temperature superconductivity (in 1986) by Bednorz and Müller in Ba-doped (hole doped) perovskite La-Cu-O system represented a significant paradigm shift in our understanding of the nature superconductivity owing (primarily) to the break down of Fermi liquid theory in the normal state. Well, heavy-fermion superconductors, despite their unconventionality, did not (relatively) attract as much attention, especially outside the superconductivity community, probably because they fell under the “low-temperature” superconductor category. Some of the most conceptually challenging (and/or puzzling) features of cuprate superconductors are the dominant role of electron-electron interactions, the microscopic origin of the unconventional superconducting gap structure (d-wave), and the existence of a “pseudogap phase” in the normal state.

This part will cover the phenomenology and contending theories of high-temperature superconductivity in the cuprates. The above article nicely summarizes the experimental and theoretical efforts aimed at understanding the universal phase diagram of cuprate superconductors, mainly focusing on antiferromagnetic, superconducting (in the so-called underdoped regime), and the pseudogap regions. A decent portion of this article focuses on a spin-liquid interpretation of certain properties of cuprates. The constrained Hilbert space of these systems can be studied using SU(2) gauge theories. This is where Shu-Ping's talk on spin-liquids might come in handy, while, at the same time, illustrating the placement of its contents into the “big picture.”

The presentation slides for this journal club meeting can be found in the PDF file here. The PDF slides are only in the reading mode; they do not contain any animations. The original PowerPoint slides with animations can be found here. If you notice any typos or scientific inaccuracies in the slides, I would be grateful if you could bring them to my attention by sending me an email.