The Brillouin zone is sampled with a Γ -centered kpoint mesh of 6×6×6 for the structural optimizations and elastic tensor calculations. Considering van der Waals interaction, Born effective charges (Z ij ) and piezoelectric e ij tensors are obtained from the self-consistent response to finite electric field as implemented using the LCAL-CEPS = .True. and IBRION = 6 tags using a k -point mesh of 3×3×3. Van der Waals interaction is not implemented VASP for Density functional perturbation theory (DFPT) calculations. Therefore DFPT is employed using the optimized structures obtained with van der Waals interactions, and we calculate the resulting piezoelectric e ij tensors. Elastic C ij tensors are obtained using the finite difference approach implemented VASP ( IBRION = 6 tag) keeping van der Waals interaction.