Coherent coupling between a quantum dot and a donor in silicon

Patrick Harvey-Collard,Michael P Lilly,Joel R Wendt,Jason Dominguez,John King Gamble,Tammy Pluym,Gregory A Ten Eyck,Malcolm S Carroll,N Tobias Jacobson,Martin Rudolph,Michel Pioro-Ladrière

doi:10.1038/s41467-017-01113-2

Abstract

Individual donors in silicon chips are used as quantum bits with extremely low error rates. However, physical realizations have been limited to one donor because their atomic size causes fabrication challenges. Quantum dot qubits, in contrast, are highly adjustable using electrical gate voltages. This adjustability could be leveraged to deterministically couple donors to quantum dots in arrays of qubits. In this work, we demonstrate the coherent interaction of a 31P donor electron with the electron of a metal-oxide-semiconductor quantum dot. We form a logical qubit encoded in the spin singlet and triplet states of the two-electron system. We show that the donor nuclear spin drives coherent rotations between the electronic qubit states through the contact hyperfine interaction. This provides every key element for compact two-electron spin qubits requiring only a single dot and no additional magnetic field gradients, as well as a means to interact with the nuclear spin qubit.

Highlights

Individual donors in silicon chips are used as quantum bits with extremely low error rates
Phosphorus donors are implanted using the accumulation gate (AG) gate as a mask. This processing maximizes the probability of placing a D in a suitable location next to the quantum dots (QDs)
Fabrication details are found in the Supplementary Note 1 and are similar to ref

Summary

Introduction

Individual donors in silicon chips are used as quantum bits with extremely low error rates. We advance silicon-based quantum information processing by coherently coupling a phosphorus donor’s electron spin to a metal-oxide-semiconductor (MOS) QD. This interaction makes the electron spin on the donor precess at a rate A/2 different from the QD electrons, where A is the hyperfine coupling strength.

Results

Conclusion