Electronic, elastic and piezoelectric properties of boron-V group binary and ternary monolayers

Highlights: • Band structures of B–V group ternary monolayers calculated by HSE are presented. • B–V group 2D monolayers are excellent piezoelectric materials with large piezoelectric response. • A volume-expansion-induced "negative pressure" effect is observed in the ternary monolayers. • A "negative pressure" effect increases the coefficient e₁₂ and piezoelectric anisotropy remarkably. • Orientation dependence mechanical and piezoelectric properties of 2D monolayers are presented. -- Abstract: Electronic, elastic, and piezoelectric properties of two-dimensional (2D) boron-V group binary and ternary monolayers are investigated by a density-functional theory (DFT) first-principle calculation. All calculated 2D monolayers show excellent piezoelectric coefficients, comparable with the frequently used bulk α-quartz (2.3 pm/V), α-SiO₂ (2.06 pm/V), and wurtzite GaN (3.1 pm/V). In particular, the e₁₂ of ternary BN_0.5P_0.5 and BN_0.5As_0.5 (−3.71 × 10⁻¹⁰ C/m and −4.66 × 10⁻¹⁰ C/m, respectively) are significantly larger than their reference binary monolayers BN (−1.35 × 10⁻¹⁰ C/m) and BP (−2.42 × 10⁻¹⁰ C/m), and BAs (−2.65 × 10⁻¹⁰ C/m). Our calculation not only expand the family of piezoelectric nano-materials, but also instruct to design new 2D piezoelectric monolayers with higher piezoelectric response by atom substitution, and to design new nano-devices that integrate piezoelectric and unique physical properties of B–V group compounds.