Princeton University

School of Engineering & Applied Science

Electrical Manipulation of Donor Spin Qubits in Silicon and Germanium

Anthony Sigillito
Engineering Quadrangle J401
Thursday, March 9, 2017 - 10:00am to 11:30am

Donor electronic and nuclear spins in silicon form two-level systems that can store quantum information for seconds, making them excellent quantum bits. These spins can typically only be controlled using microwave magnetic fields, but because magnetic fields are difficult to confine at the nanoscale, cross talk is a major concern when scaling beyond the single-qubit system. Here, I propose a solution to that problem by demonstrating a new and unexpected mechanism by which spins can be manipulated using only electric fields, which can be tightly confined.
I will first describe our resonator device which allow us to apply both electric and magnetic fields to our spins. I will then discuss the use of DC electric fields to modify the spin resonance frequency of 31P donors in silicon through modulation of the hyperfine and spin-orbit interactions. I will show evidence of electrically driven spin resonance and propose two physical mechanisms which can explain these results. If time permits, I will discuss the extension of this technique to donor spins in germanium, another promising semiconductor qubit system. Our recent measurements show that germanium is four-orders-of-magnitude more sensitive to electric fields meaning that it should allow for very fast electrically driven spin resonance.