Near-Surface 125Te+ Spins with Millisecond Coherence Lifetime

Impurity spins in crystal matrices are promising components in quantum technologies, particularly if they can maintain their spin properties when close to surfaces and material interfaces. Here, we investigate an attractive candidate for microwave-domain applications, the spins of group-VI 125Te(+) donors implanted into natural Si at depths as shallow as 20 nm. We show that surface band bending can be used to ionize such near-surface Te to spin-active Te+ state, and that optical illumination can be used further to control the Te donor charge state. We examine spin activation yield, spin linewidth, and relaxation (T-1) and coherence times (T-2) and show how a zero-field 3.5 GHz clock transition extends spin coherence times to over 1 ms, which is about an order of magnitude longer than other near-surface spin systems.

Automated summary

Impurity spins in crystal matrices, particularly group-VI 125Te(+) donors implanted into silicon surfaces, show promise in microwave-domain applications. Surface band bending can ionize near-surface Te to spin-active Te+ state, and optical illumination can further control the Te donor charge state. Zero-field 3.5 GHz clock transition extends spin coherence times to over 1 ms, an order of magnitude longer than other near-surface spin systems.