Optical properties of quantum defects from first-principles calculations*

Optical spectroscopy of point defects provides a wealth of information and, along with magnetic resonance spectroscopy, is one of the most powerful tools for defect identification and analysis. While the general theory of optical properties of defects has been formulated several decades ago, practical calculations of various properties has been far behind similar calculations for molecules and pristine solids for very good reasons. In this talk I will review several recent advances regarding the study of optical properties of defects with a special focus on quantum defects [1]: (i) the calculation of luminescence and absorption lineshapes [2], including the recently developed practical methodology to treat the multi-mode dynamical Jahn-Teller effect; (ii) radiative capture rates [3]; (iii) absolute photoionization cross-sections. The talk will be illustrated with recent examples of successful defect identification [4]. The outstanding challenges and unsolved problems will be also outlined.

Work has been performed with C. E. Dreyer, M. W. Doherty, J. L. Lyons, N. B. Manson, M. Maciaszek, M. Mackoit-Sinkeviciene, L. Razinkovas, and C. G. Van de Walle.

[1] L. C. Bassett, A. Alkauskas, A. L. Exarhos, and K.-M. C. Fu, Nanophotonics 8, 1867 (2019)
[2] A. Alkauskas, B. B. Buckley, D. D. Awschalom, and C. G. Van de Walle, New J. Phys. 16, 073023 (2014)
[3] C. E. Dreyer, J. L. Lyons, A. Alkauskas, and C. G. Van de Walle, Phys. Rev. B 102, 085305 (2020)
[4] M. Mackoit-Sinkeviciene, M. Maciaszek, C. G. Van de Walle, and A. Alkauskas, Appl. Phys. Lett. 115, 212101 (2019).