David D. Awschalom

Affiliation: University of Chicago

Date: Feb 16th, 2022; 10:00 – 11:00 (KST) / Feb 15th, 19:00 – 20:00 (CT)

Developing quantum systems with semiconductors and molecules

Our technological preference for perfection can only lead us so far: as traditional transistor-
based electronics rapidly approach the atomic scale, small amounts of disorder begin to
have outsized negative effects. Surprisingly, one of the most promising pathways out of this
conundrum may emerge from current efforts to embrace defects to construct quantum
devices and machines that enable new information processing and sensing technologies
based on the quantum nature of electrons and atomic nuclei. Individual defects in diamond,
silicon carbide, and other wide-gap semiconductors have attracted interest as they possess
an electronic spin state that can be employed as a solid-state quantum bit at room
temperature. These systems have a built-in optical interface in the visible and telecom
bands, retain their coherence over millisecond timescales, and can be polarized,
manipulated, and read out using a simple combination of light and microwaves. We discuss
integrating single spin qubits into wafer-scale, commercial optoelectronic devices, extending
the coherence of these spin qubits, and demonstrating the control and entanglement of a
single nuclear spin with an electron spin.

Optically addressable spin qubits can also be created, engineered, and scaled through a
purely synthetic chemical approach. Moreover, these structures offer new opportunities to
construct hybrid systems. We demonstrate the optical initialization and readout, and
coherent control, of ground-state spins in organometallic molecules. This bottom-up
approach offers avenues to create designer qubits and to deploy the diverse capabilities of
chemical synthesis for scalable quantum technologies.

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