Abstract
Transition metal ions provide a rich set of optically active defect spins in wide bandgap semiconductors. Chromium (Cr4+) in silicon-carbide (SiC) produces a spin-1 ground state with a narrow, spectrally isolated, spin-selective, near-telecom optical interface. However, previous studies were hindered by material quality resulting in limited coherent control. In this work, we implant Cr into commercial 4H-SiC and show optimal defect activation after annealing above 1600 °C. We measure an ensemble optical hole linewidth of 31 MHz, an order of magnitude improvement compared to as-grown samples. An in-depth exploration of optical and spin dynamics reveals efficient spin polarization, coherent control, and readout with high fidelity (79%). We report T1 times greater than 1 s at cryogenic temperatures (15 K) with a T2* = 317 ns and a T2 = 81 μs, where spin dephasing times are currently limited by spin–spin interactions within the defect ensemble. Our results demonstrate the potential of Cr4+ in SiC as an extrinsic, optically active spin qubit.
Highlights
Active defect spins in wide bandgap semiconductors have attracted much attention as candidate qubits for quantum information.[1,2] These defects hold promise due to their long lived, highly localized ground state spin states
The wide range of available point defects, including complexes and vacancies in diamond[4,5,6] and silicon-carbide (SiC)[7,8,9,10] as well as rare-earth ions in oxides,[11] offer many possible electronic, spin, and optical properties depending on their host materials
We study the creation of Cr4+ defect spins in commercial SiC through implantation and annealing, a critical step towards accurate three-dimensional localization of spin defects for device integration.[23]
Summary
Active defect spins in wide bandgap semiconductors have attracted much attention as candidate qubits for quantum information.[1,2] These defects hold promise due to their long lived, highly localized ground state spin states. They can be manipulated using a number of quantum control mechanisms[3] and interfaced with optics through atom-like spin-selective transitions for longdistance quantum communication and entanglement.[4] The wide range of available point defects, including complexes and vacancies in diamond[4,5,6] and silicon-carbide (SiC)[7,8,9,10] as well as rare-earth ions in oxides,[11] offer many possible electronic, spin, and optical properties depending on their host materials. Their magnetic fine structure within the orbitals due to the crystal field is highly host dependent and is difficult to predict.[13]
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