Description
The goal of the subproject (SP) is to study carbon systems with embedded defects, to develop new and to use gained insight into these systems by utilizing MD simulations and to transfer them via calculations of fluorescence spectra to experimental applications. Here the focus is on both the NV center and the silicon-vacancy center (SiV center) which, embedded in diamond, are interesting for a broad range of applications. Besides quantum information processing under ambient conditions, they are prime candidates for bio-magnetometry, electrometry, decoherent microscopy or even for sensitive nanothermometers.
In particular the SP examines the stability and the structure of shallow color defect centers in carbon systems. Influences of macroscopic parameters as pressure, temperature or shape of the diamond are observed using MD simulations and ab-initio calculations. As distances between the defect and the surface decreases, a destabilization and, as observed in the NV case, a transformation from the negatively charged (NV-) to a neutral (NV0) or a positive charged (NV+) defect is expected. Using various simulation techniques, these effects are to be analyzed and characterized. Furthermore, we try to influence and manipulate the fluorescence spectra by changing the surface passivation.
Placing multiple defects in the carbon lattice generates tension in the material induced by each single defect in the matrix. The aim is to calculate their influence on and to characterize the change in the fluorescence spectra. In addition the electron-phonon-coupling is under investigation and in particular the contribution of single vibrational modes to the splitting between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO).
All gained insight should be used afterwards to observe hybrids (e.g. polymers or DNA) which are adsorbed at the surface of diamonds with embedded defects. By analyzing the fluorescence spectra of the total system a quantification of the adsorbent can be obtained.