• Jafari, Homayoun
• Ramazani, Ali
• Faghihnasiri, Mahdi
• Larson, Ronald G.
• Estalaki, Sina Malakpour
• Shabani, Mostafa

Abstract

<p>Using first-principles density functional theory calculations, the mechanical and electronic properties of the three main (beta(12), chi(3), and striped) phases of single-layer borophene sheets are calculated under in-plane uniaxial/biaxial strain, including the harmonic strain-energy regions of beta(12), chi(3), and striped phases over the strain ranges of -3.5%-3.5%, -4.5%-4.5%, and -2.5%-2.5%, respectively, along the x direction (the direction of the highest bond orientation). We introduce a method by which the nonlinear behavior of these and any other two-dimensional materials can be investigated even above their ultimate strains, beyond which no-uniform plastic deformation occurs. Defining an appropriate deformation, and utilizing both continuum modeling and special equations based on the density functional theory, a method of computing second-, third-, and fourth-order elastic constants of the three different phases of borophene is presented that utilizes rectangular unit cells, which can substitute for any two-dimensional unit cell. Using this new method, 4 independent second-order, 6 third-order, and 9 fourth-order elastic constants are calculated, which is the complete set of elastic constants for two-dimensional structures. The electronic band structure of borophene shows anisotropic electronic behavior. Despite the metallic character of borophene sheets, applying directional strain based on deformation matrices creates a bandgap in some regions of the Brillouin zones, opening up the possibility of mechanical control of electronic properties. Published under license by AIP Publishing.</p>

Topics

• density
• impedance spectroscopy
• polymer
• phase
• theory
• anisotropic
• density functional theory
• two-dimensional
• band structure