  Color centers in 2-dimensional hexagonal boron nitride (h-BN) have recently
emerged as stable and bright single-photon emitters (SPEs) operating at room
temperature. In this study, we combine theory and experiment to show that
vacancy-based SPEs selectively form at nano-scale wrinkles in h-BN with its
optical dipole preferentially aligned to the wrinkle direction. By using
density functional theory calculations, we find that the wrinkle curvature
plays a crucial role in localizing vacancy-based SPE candidates and aligning
the defects symmetry plane to the wrinkle direction. By performing optical
measurements on SPEs created in h-BN single-crystal flakes, we experimentally
confirm the wrinkle-induced generation of SPEs and their polarization alignment
to the wrinkle direction. Our results not only provide a new route to
controlling the atomic position and the optical property of the SPEs but also
revealed the possible crystallographic origin of the SPEs in h-BN, greatly
enhancing their potential for use in solid-state quantum photonics and quantum
information processing.
