Role of erbium and its complex with native defect in silicon

Atomic defects in the solid state are key components of quantum repeater for long-distance quantum communication [1]. Among different candidates, erbium, the series of lanthanides, has been attracted due to its optical transition ⁴I_13/2 → ⁴I_15/2 with a corresponding wavelength of 1530 nm, which is of practical importance for telecom systems (C-band) that allow long-distance transmission in optical fiber [2,3]. Er-doped silicon is a promising platform since it can be fabricated using wafer-scale process which offer a high potential for up-scaling [4,5] and exhibit long spin-state coherence (~1.2 ms) [6]. However, doped erbium is known to easily bond to other impurities and lattice defects and forms large Er-related precipitates which cause low quantum efficiency [7,8], hence microscopic understanding of defect properties of Er and its complex with native defects is highly demand. In this work, we used density-functional calculations to investigate the formation and migration energy of Er and native defects and energetics of complex defects in silicon.