Description of quasiparticle and satellite properties via cumulant expansions of the retarded one-particle Green's function

Article

关键词: SELF-CONSISTENT GW;    ELECTRON-GAS;    ENERGIES;    SPECTRA;   

DOI  :  10.1103/PhysRevB.94.081109

来源: SCIE

【 摘 要 】

A cumulant-based GW approximation for the retarded one-particle Green's function is proposed, motivated by an exact relation between the improper Dyson self-energy and the cumulant generating function. Qualitative aspects of this method are explored within a simple one-electron independent phonon model, where it is seen that the method preserves the energy moment of the spectral weight while also reproducing the exact Green's function in the weak-coupling limit. For the three-dimensional electron gas, this method predicts multiple satellites at the bottom of the band, albeit with inaccurate peak spacing. However, its quasiparticle properties and correlation energies are more accurate than both previous cumulantmethods and standard G(0)W(0). Our results point to features that may be exploited within the framework of cumulant-based methods and suggest promising directions for future exploration and improvements of cumulant-based GW approaches.

【 授权许可】

Free