Carrier Plasmon Induced Nonlinear Band Gap Renormalization in   Two-Dimensional Semiconductors
  In reduced-dimensional semiconductors, doping-induced carrier plasmons can strongly couple with quasiparticle excitations, leading to a significant band gap renormalization. We develop a new plasmon-pole theory that efficiently and accurately capture this coupling. Using monolayer molybdenum disulfide (MoS2) as a prototype two-dimensional (2D) semiconductor, we reveal an enhanced band gap renormalization around 400 meV and an unusual nonlinear evolution of its band gap with doping. This 2D prediction significantly differs from the linear behaviors that are common to one-dimensional structures. Our developed approach allows for a quantitative understanding of many-body interactions in general doped 2D semiconductors and paves the way for novel band gap engineering techniques. 
Yufeng Liang and Li Yang
cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.other