摘要
Carrier-doped transition metal dichalcogenide(TMD)monolayers are of great interest in valleytronics due to the large Zeeman response(g-factors)in these spin-valley-locked materials,arising from many-body interactions.We develop an ab initio approach based on many-body perturbation theory to compute the interaction-enhanced g-factors in carrier-doped materials.We show that the g-factors of doped WSe2 monolayers are enhanced by screened-exchange interactions resulting from magnetic-field-induced changes in band occupancies.Our interaction-enhanced g-factors g*agree well with experiment.Unlike traditional valleytronic materials such as silicon,the enhancement in g-factor vanishes beyond a critical magnetic field Bc achievable in standard laboratories.We identify ranges of g*for which this change in g-factor at Bc leads to a valley-filling instability and Landau level alignment,which is important for the study of quantum phase transitions in doped TMDs.We further demonstrate how to tune the g-factors and optimize the valley-polarization for the valley Hall effect.
基金
This work is supported by the NUS Provost’s Office,the Ministry of Education(MOE 2017-T2-2-139)
the National Research Foundation(NRF),Singapore,under the NRF medium-sized center program.Calculations were performed on the computational cluster in the Centre for Advanced 2D Materials and the National Supercomputing Centre,Singapore.
