Linear Hyperfine Tuning of Donor Spins in Silicon Using Hydrostatic Strain.

J Mansir,M W Swift,J J Pla,Y M Niquet,P Bertet,C G Van De Walle,Z Zeng,J J L Morton,P Conti,B Sklenard,M L W Thewalt

doi:10.1103/physrevlett.120.167701

Abstract

We experimentally study the coupling of group V donor spins in silicon to mechanical strain, and measure strain-induced frequency shifts that are linear in strain, in contrast to the quadratic dependence predicted by the valley repopulation model (VRM), and therefore orders of magnitude greater than that predicted by the VRM for small strains |ϵ|<10^{-5}. Through both tight-binding and first principles calculations we find that these shifts arise from a linear tuning of the donor hyperfine interaction term by the hydrostatic component of strain and achieve semiquantitative agreement with the experimental values. Our results provide a framework for making quantitative predictions of donor spins in silicon nanostructures, such as those being used to develop silicon-based quantum processors and memories. The strong spin-strain coupling we measure (up to 150GHz per strain, for Bi donors in Si) offers a method for donor spin tuning-shifting Bi donor electron spins by over a linewidth with a hydrostatic strain of order 10^{-6}-as well as opportunities for coupling to mechanical resonators.

Highlights

Donors in silicon present an attractive spin qubit platform, offering amongst the longest coherence times in the solid state [1,2] and single-qubit control with fault-tolerant fidelity [3,4]
We experimentally study the coupling of group V donor spins in silicon to mechanical strain, and measure strain-induced frequency shifts that are linear in strain, in contrast to the quadratic dependence predicted by the valley repopulation model (VRM), and orders of magnitude greater than that predicted by the VRM for small strains jεj < 10−5
The donor electron wave function is modified by strain: following the valley repopulation model (VRM) developed by Wilson and Feher [39] within the framework of effective mass theory, an applied uniaxial strain lifts the degeneracy of the six silicon valleys leading to a mixture of the donor ground state 1sðA1Þ with the first excited state 1sðEÞ

Summary

Introduction

Donors in silicon present an attractive spin qubit platform, offering amongst the longest coherence times in the solid state [1,2] and single-qubit control with fault-tolerant fidelity [3,4]. Linear Hyperfine Tuning of Donor Spins in Silicon Using Hydrostatic Strain

Results

Conclusion