We present a GW space-time algorithm for periodic systems in a Gaussian basis including spin-orbit coupling.
We employ lattice summation to compute the irreducible density response and the self-energy, while we employ
k-point sampling for computing the screened Coulomb interaction. Our algorithm enables accurate and computationally
efficient quasiparticle band structure calculations for atomically thin transition-metal dichalcogenides.
For monolayer MoS2, MoSe2, WS2, andWSe2, computed GW band gaps agree on average within 50 meV with
plane-wave-based reference calculations. G0W0 band structures are obtained in less than two days on a laptop
(Intel i5, 192 GB RAM) or in less than 30 minutes using 1024 cores. Overall, our work provides an efficient and
scalable framework for GW calculations on atomically thin materials.