Polytype control of spin qubits in silicon carbide

TL;DR

This paper demonstrates that different polytypes of silicon carbide host coherent, optically addressable spin states with room-temperature quantum coherence, enabling engineered spin qubits for quantum information applications.

Contribution

It reveals that crystal polymorphism in silicon carbide can be used to engineer and control spin qubits with distinct properties and interactions.

Findings

All three polytypes (4H, 6H, 3C) host coherent spin states.

Room-temperature quantum coherence observed in these spins.

Dipole interactions enable potential spin network engineering.

Abstract

Crystal defects can confine isolated electronic spins and are promising candidates for solid-state quantum information. Alongside research focusing on nitrogen vacancy centers in diamond, an alternative strategy seeks to identify new spin systems with an expanded set of technological capabilities, a materials driven approach that could ultimately lead to "designer" spins with tailored properties. Here, we show that the 4H, 6H and 3C polytypes of SiC all host coherent and optically addressable defect spin states, including spins in all three with room-temperature quantum coherence. The prevalence of this spin coherence shows that crystal polymorphism can be a degree of freedom for engineering spin qubits. Long spin coherence times allow us to use double electron-electron resonance to measure magnetic dipole interactions between spin ensembles in inequivalent lattice sites of the same crystal. Together with the distinct optical and spin transition energies of such inequivalent spins, these interactions provide a route to dipole-coupled networks of separately addressable spins.