Excited State Structure of Defected Solids (Co@S:WS2 and Si G-Center) through GW/Bethe Salpeter Equation (GW/BSE) Approaches
Arabi Seshappan (UCLA)
Defects in solid state materials have been identified as candidates for application in quantum information science (QIS) as single photon emitters, quantum light sources, and room-temperature solid-state quantum bits (qubits). Accurate calculations of the exciton (coupled electron-hole pair) interactions in these materials is imperative to understanding these applications. In this work I study the ground- and excited-state energies for 2 promising QIS defected-solid candidates, using the many-body perturbation theory of the GW approximation and the Bethe-Salpeter Equation (BSE) approach. I show initial results of vertical excitation energies for monolayer cobalt-at-sulfur-site substituted WS2 (Co@S:WS2), using a novel method of Spin-Flip on BSE [arXiv:2207.04549]. I will also discuss preliminary calculations of optical spectra of the Si G-center defect—diamond structure Si with a C-Si-C substitution—using conventional GW/BSE through the open-source code BerkeleyGW. These defected structures are of particular interest due to their ease of fabrication and emissions compatibility with current optical fiber/ telecommunications infrastructure.