2022/03/11 by Codony, David, Arias, Irene, Suryanarayana, Phanish
#Computational Physics (physics.comp-ph) #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
paper · doi:10.48550/arxiv.2203.06132
In a recent letter [Phys. Rev. Lett. 127, 216801 (2021)], the authors introduced the effective flexoelectric coefficient μ^\textrm2D for quantifying the flexoelectric effect in 2D systems, and reported a disagreement with the flexoelectric coefficient μT introduced in Ref. [Phys. Rev. Mat. 5, L030801 (2021)], attributed to the neglect of the metric term φM -- quadrupolar moment of the unperturbed charge density -- in the formulation of Ref. [Phys. Rev. Mat. 5, L030801 (2021)]. Here, we show that the model in Ref. [Phys. Rev. Mat. 5, L030801 (2021)] is correct and is in agreement with that in Ref. [Phys. Rev. Lett. 127, 216801 (2021)]. The discrepancies in the numerical values of the coefficients arise due to the difference in their definitions: μ_\textrmT measures changes in bending-induced out-of-plane polarization, whereas μ^\textrm2D measures changes in bending-induced voltage drop across the 2D system.