General procedure for the calculation of accurate defect excitation energies from DFT-1/2 band structures: The case of the NV− center in diamond
| Autor: | Bruno Lucatto, Lucy V. C. Assali, Lara K. Teles, Marcelo Marques, R. R. Pelá |
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| Rok vydání: | 2017 |
| Předmět: |
Physics
Band gap Center (category theory) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Computational physics Ab initio quantum chemistry methods Qubit 0103 physical sciences Quasiparticle Quantum system Atomic physics 010306 general physics 0210 nano-technology Electronic band structure Quantum computer |
| Zdroj: | Physical Review B. 96 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.96.075145 |
| Popis: | A major challenge in creating a quantum computer is to find a quantum system that can be used to implement the qubits. For this purpose, deep centers are prominent candidates, and ab initio calculations are one of the most important tools to theoretically study their properties. However, these calculations are highly involved, due to the large supercell needed, and the computational cost can be even larger when one goes beyond the Kohn-Sham scheme to correct the band gap problem and achieve good accuracy. In this work, we present a method that overcomes these problems and provides the optical transition energies as a difference of Kohn-Sham eigenvalues; even more, provides a complete and accurate band structure of the defects in a semiconductor. Despite the original motivations, the presented methodology is a general procedure, which can be used to systematically study the optical transitions between localized levels within the band gap of any system. The method is an extension of the low-cost and parameter-free DFT-1/2 approximate quasiparticle correction, and allows it to be applied in the study of complex defects. As a benchmark, we apply the method to the ${\mathrm{NV}}^{\ensuremath{-}}$ center in diamond. The agreement with experiments is remarkable, with an accuracy of 0.1 eV. The band structure agrees with the expected qualitative features of this system, and thus provides a good intuitive physical picture by itself. |
| Databáze: | OpenAIRE |
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