Strain-induced spin resonance shifts in silicon devices

TL;DR

This study investigates how strain from on-chip circuitry affects spin resonance frequencies in silicon-based quantum devices, using simulations and experiments to understand and predict these shifts for improved device performance.

Contribution

It demonstrates the impact of strain-induced resonance shifts in silicon quantum devices and models these effects using finite-element simulations and experimental ESR data.

Findings

Resonance shifts are significant compared to intrinsic line-widths.

Strain causes hyperfine interaction shifts proportional to hydrostatic strain.

Finite-element simulations successfully reproduce experimental ESR spectra.

Abstract

In spin-based quantum information processing devices, the presence of control and detection circuitry can change the local environment of a spin by introducing strain and electric fields, altering its resonant frequencies. These resonance shifts can be large compared to intrinsic spin line-widths and it is therefore important to study, understand and model such effects in order to better predict device performance. Here we investigate a sample of bismuth donor spins implanted in a silicon chip, on top of which a superconducting aluminium micro-resonator has been fabricated. The on-chip resonator provides two functions: first, it produces local strain in the silicon due to the larger thermal contraction of the aluminium, and second, it enables sensitive electron spin resonance spectroscopy of donors close to the surface that experience this strain. Through finite-element strain simulations we are able to reconstruct key features of our experiments, including the electron spin resonance spectra. Our results are consistent with a recently discovered mechanism for producing shifts of the hyperfine interaction for donors in silicon, which is linear with the hydrostatic component of an applied strain.