Electrically controlled dielectric band gap engineering in a two-dimensional semiconductor

This work proposes and investigates a new physical concept of electrically controlled dielectric band gap engineering in a two-dimensional (2D) semiconductor. The authors show, using first-principles many-body calculations, that the band gap of a 2D semiconductor can be varied by several hundred meV's by varying the doping concentration in a supporting graphene sheet as illustrated in the accompanying image. This provides a method for continuous and dynamical $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0.333em}{0ex}}s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ tuning of the band gap. Importantly, the band gap adjustment is achieved via nonlocal Coulomb interactions and does not involve changes in the atomic structure, or even the shape or hybridization pattern, of the wave functions of the 2D semiconductor.