Photoemission Spectra from Reduced Density Matrices: the Band Gap in Strongly Correlated Systems

Abstract

We present a method for the calculation of photoemission spectra in terms of reduced density matrices. We start from the spectral representation of the one-body Green's function G, whose imaginary part is related to photoemission spectra, and we introduce a frequency-dependent effective energy that accounts for all the poles of G. Simple approximations to this effective energy give accurate spectra in model systems in the weak as well as strong correlation regime. In real systems reduced density matrices can be obtained from reduced density-matrix functional theory. Here we use this approach to calculate the photoemission spectrum of bulk NiO: our method yields a qualitatively correct picture both in the antiferromagnetic and paramagnetic phases, contrary to mean-field methods, in which the paramagnet is a metal.

References in corpus (7)

• Reduced Density Matrix Functional for Many-Electron Systems
• NiO: Correlated Bandstructure of a Charge-Transfer Insulator
• Band widths and gaps from the Tran-Blaha functional : Comparison with many-body perturbation theory
• Unbiased Reduced Density Matrices and Electronic Properties from Full Configuration Interaction Quantum Monte Carlo
• Beyond the GW approximation: combining correlation channels
• GW method applied to localized 4f electron systems
• Spectral density of the Hubbard-model by the continued fraction method

Cited by in corpus (1)

• Scrutinizing $GW$-based methods using the Hubbard dimer