Piezoelectric effects on the resonance frequencies of boron nitride nanosheets

Abstract

By using molecular dynamics (MD) simulations, we find in this work that due to the piezoelectric characteristic of boron nitride (BN) nanosheets their resonance frequencies can be efficiently tuned by applying an external electric field. This finding suggests that BN nanosheet can be treated as a good building block for designing novel piezoelectrically tunable two-dimensional nanoresonators. As BN nanosheets possess an inversely stacked structure, the applied electric field has different effects on the resonance frequency of BN nanosheets with odd and even layers. The influence of piezoelectric effect on the vibration behaviours observed in MD simulations is found to significantly deviate from the prediction of the conventional Euler-Bernoulli beam model (EBM), since the EBM cannot account for the weak van der Waals interaction between neighbouring layers in BN nanosheets. To take into account the interlayer interaction in the mathematical modelling of the piezoelectric effect on the vibration of BN nanosheets, we propose here a novel multiple beam model (MBM), which can account for both interlayer stretching and shearing deformations. The MBM result is found to be in a good agreement with the MD result without any additional parameters fitting, which indicates that the present MBM can be treated as a more precise theoretical model in the future study of the vibration properties of BN nanosheets.

A nonlocal continuum model for the piezopotential of two-dimensional semiconductors

“…Here, the calculation of e was based on its definition e = dP/dλ, where P is the polarization induced by the strain λ originating from the axial expansion of hBN nanosheets. The axial piezoelectric coefficient e obtained here is 0.42 C m −2 , which is close to the results reported in the previous studies [68]. In the calculation, the effective thickness of monolayer hBN was chosen as 3.33 Å [68], which equals to the interlayer spacing of bulk hBN.…”

“…The axial piezoelectric coefficient e obtained here is 0.42 C m −2 , which is close to the results reported in the previous studies [68]. In the calculation, the effective thickness of monolayer hBN was chosen as 3.33 Å [68], which equals to the interlayer spacing of bulk hBN.…”

Shape- and size dependent piezoelectric properties of monolayer hexagonal boron nitride nanosheets

“…Previous studies indicate that uniaxial polarization only exists along the armchair direction of h-BN, 17,44 and the piezoelectric properties were determined by stretching the structure along the armchair direction and recording the polarization changes, 2,26,47 i.e. , by using e 11 = ∂ P 1 /∂ ε 1 .…”

“…Hence, we use the general form for in-plane strains, eqn (9) and (10), to calculate the piezoelectric constants of nite structures. Previous studies indicate that uniaxial polarization only exists along the armchair direction of h-BN, 17,44 and the piezoelectric properties were determined by stretching the structure along the armchair direction and recording the polarization changes, 2,26,47 i.e., by using e 11 ¼ vP 1 /v3 1 . When a shear strain is applied, a polarization change along the zigzag direction is obtained.…”

“…14 2D materials already show interesting potential as nanosensors and for medical applications. 15,16 Hexagonal boron nitride (h-BN) is one of the most promising materials because of its high elastic modulus and optical properties which renders h-BN a good candidate as a nanoresonator 17 or luminous material. 18 Watanabe et al 19 studied the potential of h-BN as a far-ultraviolet uorescent material and fabricated stable far-ultraviolet plane-emission device with high output by using h-BN powder.…”