Strain-Induced Changes in Vibrational Properties of Arsenene and Antimonene

Strain is an unavoidable factor which builds inherently during the synthesis of two-dimensional (2D) materials affecting the material’s properties, whereas many times strain is also useful when it comes to tuning of material’s properties. In recent years, arsenene and antimonene have been widely studied for their tunable bandgap with the application of strain. Therefore, characterizing and quantifying induced strain on arsenene and antimonene are of utmost importance in their experimental studies. In this work, we investigate the vibrational properties of arsenene and antimonene monolayer under biaxial strain using phonon dispersion curves and Raman spectral calculations. Both arsenene and antimonene are dynamically stable up to 10% stretching biaxial strain, whereas they are dynamically unstable under the compressive biaxial strain. The quadratic turned linear behaviour of ZA mode of arsenene and antimonene at 10% indicates that the removal of rippling under biaxial strain follows shell elasticity model. All the optical phonon modes of arsenene and antimonene are Raman active and sensitive to strain, and hence Raman spectral measurements can efficiently characterize strain in arsenene and antimonene. The Raman intensity of in-plane mode (E2g) is less than that of out plane mode (A1g) at strain-free condition, whereas the former becomes higher at large biaxial strain. The weakening of bond strength caused by increasing biaxial strain lowers the E2g mode and A1g mode of arsenene and antimonene. A1g mode behaves linearly with the strain, whereas E2g mode follows quadratic relation with biaxial strain.