Two-particle response in Cluster Dynamical Mean-Field Theory: Formalism and application to the Raman Response of High-temperature Superconductors

TL;DR

This paper introduces a new numerical method for calculating two-particle response functions in correlated electron systems, demonstrated on high-temperature superconductor models, revealing key spectral features and their evolution with doping.

Contribution

It presents an unbiased numerical approach for two-particle responses within dynamical mean-field theory, applicable to complex correlated materials.

Findings

Reproduces the two-magnon peak in Raman spectra of insulating cuprates.

Shows evolution of Raman response from insulator to doped superconductor.

Method applicable to any system solvable by dynamical mean-field theory.

Abstract

A method is presented for the unbiased numerical computation of two-particle response functions of correlated electron materials via a solution of the dynamical mean-field equations in the presence of a perturbing field. The power of the method is demonstrated via a computation of the Raman $B_{1g}$ and $B_{2g}$ scattering intensities of the two dimensional Hubbard model, in parameter regimes believed to be relevant to high-temperature superconductivity. The theory reproduces the `two-magnon' peak characteristic of the Raman intensity of the insulating parent compounds of high-$T_c$ copper oxide superconductors and shows how it evolves to a quasiparticle response as carriers are added. The method can be applied in any situation where a solution of the equilibrium dynamical mean-field equations is feasible.