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Optical addressing of an individual erbium ion in silicon
Chunming Yin, Milos Rancic, Gabriele G. de Boo, Nikolas Stavrias, Jeffrey C. McCallum, Matthew J. Sellars, Sven Rogge
TL;DR
The paper develops an experimental platform for studying erbium in silicon using implanted, annealed devices and cryogenic optical measurements. It defines a nanoscale SET-sensitive region, applies controlled wavelength sweeps, and identifies single-ion ionization through two-level current traces.
Problem
The supplied experimental passages establish the need to study optically induced erbium-ionization signals in a nanoscale silicon charge-sensing region.
Method
The study combines Er:O implantation and annealing with 4.2 K laser measurements around a silicon SET Coulomb peak.
Results
Two-level current traces are consistent with ionization of a single Er3+ ion.
Takeaways & Limitations
The measurements provide an electrical signature for distinguishing single-ion ionization from signals involving multiple ions.
Abstract
from arXiv · showhide
The detection of electron spins associated with single defects in solids is a critical operation for a range of quantum information and measurement applications currently under development. To date, it has only been accomplished for two centres in crystalline solids: phosphorus in silicon using electrical readout based on a single electron transistor (SET) and nitrogen-vacancy centres in diamond using optical readout. A spin readout fidelity of about 90% has been demonstrated with both electrical readout and optical readout, however, the thermal limitations of the electrical readout and the poor photon collection efficiency of the optical readout hinder achieving the high fidelity required for quantum information applications. Here we demonstrate a hybrid approach using optical excitation to change the charge state of the defect centre in a silicon-based SET, conditional on its spin state, and then detecting this change electrically. The optical frequency addressing in high spectral resolution conquers the thermal broadening limitation of the previous electrical readout and charge sensing avoids the difficulties of efficient photon collection. This is done with erbium in silicon and has the potential to enable new architectures for quantum information processing devices and to dramatically increase the range of defect centres that can be exploited. Further, the efficient electrical detection of the optical excitation of single sites in silicon is a major step in developing an interconnect between silicon and optical based quantum computing technologies.
METHOD SUMMARY
The study uses erbium-implanted silicon devices, annealed to form Er centres, with cryogenic, high-resolution laser measurements for optical excitation and detection.
- METHOD SUMMARY: Approximately 30–40 Er ions occupy the sensitive region of one Coulomb peak after Er:O co-implantation.The implantation uses a 1:6 Er:O dose ratio and energies of 400 keV and 55 keV, respectively.
- METHOD SUMMARY: Measurements are performed at 4.2 K using a 4–5 mW laser beam delivered through a single-mode fibre onto a roughly 1 mm spot.
- METHOD SUMMARY: High-resolution experiments stabilize the laser wavelength to about 0.01 pm and compensate thermal drift with a wavelength meter.
METHODS
The experiments use a silicon SET’s corner-region Coulomb peak as a sensitive charge-sensing environment for optically induced Er-ionization events and resolve single-ion signatures.
- METHODS: Measurements are conducted at 4.2 K with 4–5 mW laser illumination delivered through a single-mode fibre.
- METHODS: A motor actuator sets the central wavelength while a piezo actuator sweeps around it during the initial measurements.
- METHODS: A two-level current trace indicates ionization of one Er3+ ion, whereas multiple ions with different capacitive couplings produce more than two levels.At one example detuning, the current jumps between 1.8 nA and 0.4 nA.