Electron-hole or quasiparticle representation plays a central role in describing electronic excitations in many-electron systems. For charge-neutral excitation, the electron-hole interaction kernel is the quantity of interest for calculating important excitonic and biexcitonic properties. The accurate determination of the electron-hole interaction kernel remains a significant challenge for precise calculations of optical properties in the Green’s function many-body perturbation theory formalism. Traditional approaches, such as MBPT formalism, use unoccupied states (which are defined with respect to Fermi vacuum) to construct the electron-hole interaction kernel. However, the inclusion of unoccupied states has long been recognized as the leading computational bottleneck that limits the application of this approach for larger finite systems. In this work, we present an alternative derivation that avoids using unoccupied states to construct the electron-hole interaction kernel. The central idea of our approach is to use real-space correlation operators for treating electron-electron correlation for both ground and excited state wave functions. This method, known as the geminal-screened electron-hole interaction kernel (GSIK) demonstrates that the renormalized operators appearing in the real-space representation are equivalent to infinite-order summations of particle-hole diagrams in the occupation-number representation. The GSIK method was applied to calculate excitonic and biexcitonic binding energies in various semiconductor (CdSe, CdS, PbSe, PbS, ZnSe) clusters and quantum dots. The numerical results highlight the effectiveness of the developed method for overcoming the computational barrier of accurately determining the electron-hole interaction kernel to applications of large finite systems such as quantum dots and nanorods.

Electron-hole screening in excitonic and biexcitonic systems: A real-space perspective

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.