We analysed strain of the exfoliated hBN layers using the Peak Pairs Analysis (PPA) software package (HREM research) for Gatan Digital Micrograph. For the analysis, we employed low-pass filtered HRTEM images of the non-twisted hBN layers. The peak positions were determined on the filtered image, and the relative displacement fields (ux, uy) of the measured lattice with respect to a reference basis vector were calculated. The components of strain tensor 𝜀 𝑥𝑥 , 𝜀 𝑥𝑦 , 𝜀 𝑦𝑦 , mean dilatation ∆ 𝑥𝑦 , rotation 𝜔 𝑥𝑦 (in radians) are defined as follows: