Chapter 203 Electronic and magnetic raman scattering studies of the high-Tc cuprates

Abstract

This chapter reviews the Raman scattering studies of the many diverse phases of high-Tc superconductors. In many respects, Raman scattering is a natural probe of the cuprates. As a technique that is sensitive to spin, electronic, and phonon degrees of freedom, Raman scattering can provide energy, symmetry, and lifetime information about many of the diverse excitations present throughout the complex phase diagram of the cuprates. Moreover, Raman scattering provides an ideal method with which to explore the evolution of charge, spin, and lattice excitations among different phases. Raman scattering lends itself particularly to the study of such important issues as the nature of the superconducting pairing mechanism, the manner in which antiferromagnetic correlations evolve into the metallic phase, and the relationship between “pseudogap” and superconducting phases in underdoped cuprates. The chapter describes the Raman scattering response in the insulating phase, focusing on scattering from two-magnon excitations, topological (chiral) spin excitations, excitons, and crystal-field excitations.