Petros-Panagis Filippatos, Tom J. P. Irons, Navaratnarajah Kuganathan, Alexander Chroneos
Point defects in two-dimensional and layered materials have attracted considerable interest as promising qubit candidates for quantum information processing due to their highly localized electronic states and spin-dependent optical properties. In this work, we use r 2 SCAN density functional calculations combined with complete active space self-consistent field theory to investigate bulk carbon-doped tungsten disulfide ( WS 2 ) as a potential platform for scalable quantum technologies. The meta-generalized gradient approximation exchange-correlation functional r 2 SCAN is found to offer a balance between accuracy and computational efficiency for specific properties, while its performance has not been tested in bulk WS 2 before. By substituting sulphur atoms with carbon impurities, we achieve stable paramagnetic excited states characterized by well-defined defect levels deep within the band gap. Moreover, we investigate the zero-phonon line, radiative lifetime, and zero-field splitting due to the carbon impurities. The presence of tungsten introduces relativistic effects which are desired for some quantum applications, facilitating efficient initialization, coherent manipulation, and readout of defect spin states. We elucidate the role of carbon in lowering the emission energies into technologically relevant wavelengths for quantum information science, while we compare the present results with the extensively investigated monolayer structure. Our results highlight carbon-doped WS 2 as an attractive solid-state quantum platform due to its zero-phonon line, zero-field splitting, and radiative lifetime values, enabling robust optical control and manipulation of spin states for quantum applications.