Fig. 3: Effect of curvature-induced flexoelectricity on the band-edge levels of MoSe2 nanotubes.
From: Curvature-controlled band alignment transition in 1D van der Waals heterostructures
a DFT-calculated electrostatic potential profile in a MoSe2 (14,0) nanotube. b Calculated flexovoltages (filled blue dots) and average local electrostatic potential changes at the Mo site (\({{\Delta }}{V}_{{{{\rm{core}}}}}\), open green hexagons) as a function of inverse diameter 1/D. The lines are linear extrapolations of each set of data in the large-diameter limit. c Effect of flexoelectricity-induced electrostatic potential energy shift on the band-edge level evolution of MoSe2 zigzag nanotubes. The filled circles are the VBM and CBM levels of MoSe2 nanotubes from actual DFT calculations. The open circles represent the model band-edge levels of MoSe2 nanotubes obtained by adding the VBM/CBM energy levels of MoSe2 monolayer (VBMmono and CBMmono) with the average electrostatic potential energy shift (\({{\Delta }}{E}_{{{{\rm{core}}}}}=-| e| {{\Delta }}{V}_{{{{\rm{core}}}}}\), where e is the elementary charge) at the corresponding tube diameter.
