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HL: Fachverband Halbleiterphysik
HL 49: Quantum Emitters in 2D Semiconductors
HL 49.4: Vortrag
Donnerstag, 12. März 2026, 17:15–17:30, POT/0081
Thermodynamic properties of quantum defects in boron nitride using machine-learned force fields — •Ariel Moises Cabrera Aguilar and Carla Verdi — The University of Queensland, Brisbane, Australia
Hexagonal boron nitride (hBN) has emerged as an excellent host material for bright single-photon emitters. Experimental and computational studies associate these single-photon emitters (SPEs) in hBN predominantly with carbon-related defects. However, the lack of first-principles calculations at finite temperatures and with sufficiently large supercells hinders the establishment of a consensus on the most likely defect candidates for quantum-technology applications. Machine-learned force fields (MLFFs) provide highly accurate finite-temperature simulations because they can be trained to reproduce first-principles energies and forces across diverse configurations. We trained a MLFF capable of describing various carbon cluster defects (CB, CN, CB CN, CB VN, CB Ci, and CN Ci) at temperatures up to approximately 2000 K. To evaluate the accuracy of the force field in reproducing atomic positions, interatomic energies, and forces across these structures, we compute formation energies, phonon dispersions, and photoluminescence spectra, and compare these quantities with available experimental data. The force field successfully reproduces the line shape of several defects in multilayered systems of different supercell sizes. The MLFF is used to investigate multiple defects in large supercells over long molecular dynamics simulation times, allowing us to capture metastable structures that emerge at finite temperature.
Keywords: hexagonal boron nitride; 2D materials; point defects; quantum emitters; density functional theory