Ab-initio studies of exciton g factors: Monolayer transition metal dichalcogenides in magnetic fields
Abstract
The effect of a magnetic field on the optical absorption in semiconductors has been measured experimentally and modeled theoretically for various systems in previous decades. We present a new first-principles approach to systematically determine the response of excitons to magnetic fields, i.e. exciton g factors. By utilizing the GW-Bethe-Salpeter equation methodology we show that g factors extracted from the Zeeman shift of electronic bands are strongly renormalized by many-body effects which we trace back to the extent of the excitons in reciprocal space. We apply our approach to monolayers of transition metal dichalcogenides (MoS2, MoSe2, MoTe2, WS2, and WSe2) with strongly bound excitons for which g factors are weakened by about 30%.
0