Negative-U properties for substitutional Au in Si
1 CIC nanoGUNE - 20018 Donostia-San Sebastián, Spain
2 Departments of Materials and Physics, and the Thomas Young Centre for Theory and Simulation of Materials, Imperial College London - London SW7 2AZ UK
Received: 5 December 2013
Accepted: 6 March 2014
The isolated substitutional gold impurity in bulk silicon is studied in detail using electronic structure calculations based on density-functional theory. The defect system is found to be a non–spin-polarized negative-U centre, thus providing a simple solution to the long-standing debate over the electron paramagnetic resonance signal for gold in silicon. There is an excellent agreement (within 0.03 eV) between the well-established experimental donor and acceptor levels and the predicted stable charge state transition levels, allowing for the unambiguous assignment of the two experimental levels to the and transitions, respectively, in contrast to previously held assumptions about the system.
PACS: 71.55.Cn – Elemental semiconductors / 61.72.J- – Point defects and defect clusters / 71.15.Mb – Density functional theory, local density approximation, gradient and other corrections
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