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arXiv · 2006.16474

Photoluminescence and photochemistry of the $V_B^-$ defect in hexagonal boron nitride

Jeffrey R. Reimers·Jun Shen·Mehran Kianinia·Carlo Bradac·Igor Aharonovich·Michael J. Ford·Piotr Piecuch
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Abstract

Extensive photochemical and spectroscopic properties of the $V_B^-$ defect in hexagonal boron nitride are calculated, concluding that the observed photoemission associated with recently observed optically-detected magnetic resonance is most likely of (1)3E" to (1)3A2' origin. Rapid intersystem crossing from the defect's triplet to singlet manifolds explains the observed short excited-state lifetime and very low quantum yield. New experimental results reveal smaller intrinsic spectral bandwidths than previously recognized, interpreted in terms spectral narrowing and zero-phonon-line shifting induced by the Jahn-Teller effect. Different types of computational methods are applied to map out the complex triplet and singlet defect manifolds, including the doubly ionised formulation of the equation-of-motion coupled-cluster theory that is designed to deal with the open-shell nature of defect states, and mixed quantum-mechanics/molecular-mechanics schemes enabling 5763-atom simulations. Two other energetically feasible spectral assignments from amongst the singlet and triplet manifolds are considered, but ruled out based on inappropriate photochemical properties.

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Jeffrey R. Reimers, Jun Shen, Mehran Kianinia, Carlo Bradac, Igor Aharonovich, Michael J. Ford, Piotr Piecuch. 2020-06-30. Photoluminescence and photochemistry of the $V_B^-$ defect in hexagonal boron nitride. https://doi.org/10.1103/physrevb.102.144105

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