Second-order Green's function perturbation theory for periodic systems

TL;DR

This paper introduces a periodic implementation of the self-consistent 2nd-order Green's function method (GF2) for extended systems, demonstrating its ability to describe various electronic phases in a 1D hydrogen lattice.

Contribution

The paper develops a computationally feasible periodic GF2 method and applies it to a 1D hydrogen lattice, capturing metallic, insulating, and Mott regimes.

Findings

GF2 can recover metallic, band insulating, and Mott regimes.

Iterative GF2 is crucial for the emergence of metallic and Mott phases.

The method provides a promising approach for treating electron correlation in periodic systems.

Abstract

Despite recent advances, systematic quantitative treatment of the electron correlation problem in extended systems remains a formidable task. Systematically improvable Green's function methods capable of quantitatively describing weak and at least qualitatively strong correlations appear promising candidates for computational treatment of periodic systems. We present a periodic implementation of temperature-dependent self-consistent 2nd-order Green's function method (GF2), where the self-energy is evaluated in the basis of atomic orbitals. Evaluating the real-space self-energy in atomic orbitals and solving the Dyson equation in $\mathbf{k}$-space are the key components of a computationally feasible algorithm. We apply this technique to the 1D hydrogen lattice - a prototypical crystalline system with a realistic Hamiltonian. By analyzing the behavior of the spectral functions, natural occupations, and self-energies, we claim that GF2 is able to recover metallic, band insulating, and at least qualitatively Mott regimes. We observe that the iterative nature of GF2 is essential to the emergence of the metallic and Mott phases.