Electron Spin Resonance of P Donors in Isotopically Purified Si Detected by Contactless Photoconductivity

Abstract

Coherence times of electron spins bound to phosphorus donors have been measured, using a standard Hahn echo technique, to be up to 20 ms in isotopically pure silicon with [P]$=10^{14}$ cm${}^{-3}$ and at temperatures $\le 4$K. Although such times are exceptionally long for electron spins in the solid state, they are nevertheless limited by donor electron spin-spin interactions. Suppressing such interactions requires even lower donor concentrations, which lie below the detection limit for typical electron spin resonance (ESR) spectrometers. Here we describe an alternative method for phosphorus donor ESR detection, exploiting the spin-to-charge conversion provided by the optical donor bound exciton transition. We characterise the method and its dependence on laser power and use it to measure a coherence time of $T_2=130$ms for one of the purest silicon samples grown to-date ([P]$=5\times 10^{11}$cm${}^{-3}$). We then benchmark this result using an alternative application of the donor bound exciton transition: optically polarising the donor spins before using conventional ESR detection at 1.7~K for a sample with [P]$=4\times 10^{12}$cm${}^{-3}$, and measuring in this case a $T_2$ of 350 ms.

References in corpus (14)

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• Storing quantum information for 30 seconds in a nanoelectronic device
• Room temperature quantum bit storage exceeding 39 minutes using ionized donors in 28-silicon
• Atomic clock transitions in silicon-based spin qubits
• Electron spin decoherence in isotope-enriched silicon
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• A long-lived Zeeman trapped-ion qubit
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• Electrically-detected magnetic resonance in ion-implanted Si:P nanostructures
• $T_1$- and $T_2$-spin relaxation time limitations of phosphorous donor electrons near crystalline silicon to silicon dioxide interface defects
• Conditional control of donor nuclear spins in silicon using Stark shifts
• Hybrid optical-electrical detection of donor electron spins with bound excitons in silicon
• Electron nuclear double resonance with donor-bound excitons in silicon

Cited by in corpus (4)

• Spin resonance linewidths of bismuth donors in silicon coupled to planar microresonators
• Spin rotation by resonant electric field in few-level quantum dots: Floquet dynamics and tunneling
• Strain effects in phosphorous bound exciton transitions in silicon
• Strained Donor-Bound Excitons in ${}^{28}$Si