Vacancy in silicon revisited: structure and pressure effects

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOThe structure of the single vacancy in silicon. one of the most common point defects and an important mediator of atomic diffusion, is examined through extensive first principles calculations. We find a hitherto unexpected result, namely that there exist two distinct distortions associated with the vacancy with essentially identical formation energies at zero pressure. The two distortions are distinguished by their different relaxations, volumes of formation, and :formation enthalpies. We discuss how, at finite pressure, one of the two distortions should become dominant, and suggest experimental tests of this effect.The structure of the single vacancy in silicon, one of the most common point defects and an important mediator of atomic diffusion, is examined through extensive first principles calculations. We find a hitherto unexpected result, namely that there exist two distinct distortions associated with the vacancy with essentially identical formation energies at zero pressure. The two distortions are distinguished by their different relaxations, volumes of formation, and formation enthalpies. We discuss how, at finite pressure, one of the two distortions should become dominant, and suggest experimental tests of this effect.811020882091FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSem informaçãoSem informaçãoWe thank Professor M. J. Aziz for useful discussions throughout this work and helpful comments on the manuscript. A. A. wishes to thank Harvard University for its hospitality during the course of this work, and to acknowledge partial support from the Brazilian funding agencies Fundo de Apoio ao Ensino e à Pesquisa (FAEP/UNICAMP), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). Computer calculations were performed at the facilities of the Centro Nacional de Processamento de Alto Desempenho em São Paulo (CENAPAD-SP). The work at Harvard University was supported the Materials Science and Engineering Center, which is funded by the National Science Foundation