Physical Review Letters
Convergence Behavior of Many-Body Perturbation Theory with Lattice Summations in Polymers
Jun-Qiang Sun, Rodney J. Bartlett
Abstract
The convergence behavior of many-body perturbation theory (MBPT) with lattice summations directly reflects the spatial property of electron correlation in extended systems. A knowledge of such properties is essential for both theory and numerical calculations. It is shown solely from theory that the second-order MBPT contribution to the total energy per unit cell in polymers converges with lattice size $N$ as $1/{N}^{3}$ while the second-order MBPT contribution to the band energy converges as $1/{N}^{2}$. These convergence behaviors are demonstrated numerically for polyacetylene.