First principles calculation of valley g-factors in transition metal dichalcogenide monolayers, with dynamical self-energy effects.

H-phase transition metal dichalcogenide (TMD) monolayers (MLs) have two distinct energy valleys, and are therefore promising for valleytronic applications, in which the valley degree of freedom is controlled for information storage and processing. In the presence of an out-of-plane magnetic field, the two valleys are shifted in opposite directions (the Zeeman effect), and reorganised into discrete equally-spaced levels (Landau Levels). The Zeeman effect is quantified by the Landé g-factor. Here, we develop an approach which provides quantitative predictions of the g-factors, taking into account many-body interactions from first principles.[Phys. Rev. Res. 2, 033256; npj Comput. Mater. 7, 198] We show that dynamical self-energy effects can significantly enhance the g-factors of doped ML TMDs, compared to undoped TMDs.[npj Comput. Mater. 7, 198] The predicted g-factors are in excellent agreement with experimentally-determined doping-density-dependent enhanced valley g-factors, g*.[Phys. Rev. Lett. 125, 147602] This enhancement effect is shown to orginate from the varying screened exchange interaction in response to the change of doping density in the two valleys. We predict the presence of a critical magnetic field after which this enhencement effect will disappear. Our calculated critical magnetic fields agree with recent experimental measurements.[Phys. Rev. Lett. 125, 147602]