Many-body perturbation theory approach to the electron-phonon interaction with density-functional theory as a starting point

Article

关键词: TEMPERATURE-DEPENDENCE;    AB-INITIO;    LINEAR-RESPONSE;    DIRECT-GAP;    BAND-GAPS;    EXCITATIONS;    SPECTRA;    SOLIDS;    SI;   

DOI  :  10.1103/PhysRevB.91.224310

来源: SCIE

【 摘 要 】

The electron-phonon interaction plays a crucial role in many fields of physics and chemistry. Nevertheless, its actual calculation by means of modern many-body perturbation theory is weakened by the use of model Hamiltonians that are based on parameters difficult to extract from the experiments. Such shortcoming can be bypassed by using density-functional theory to evaluate the electron-phonon scattering amplitudes, phonon frequencies, and electronic bare energies. In this work, we discuss how a consistent many-body diagrammatic expansion can be constructed on top of density-functional theory. In that context, the role played by screening and self-consistency when all the components of the electron-nucleus and nucleus-nucleus interactions are taken into account, is paramount. A way to avoid overscreening is notably presented. Finally, we derive cancellation rules as well as internal consistency constraints in order to draw a clear, sound, and practical scheme to merge the many-body perturbation and density-functional theory.

【 授权许可】

Free