Strain engineering of the silicon-vacancy center in diamond (1801.09833v2)

Abstract: We control the electronic structure of the silicon-vacancy (SiV) color-center in diamond by changing its static strain environment with a nano-electro-mechanical system. This allows deterministic and local tuning of SiV optical and spin transition frequencies over a wide range, an essential step towards multi-qubit networks. In the process, we infer the strain Hamiltonian of the SiV revealing large strain susceptibilities of order 1 PHz/strain for the electronic orbital states. We identify regimes where the spin-orbit interaction results in a large strain suseptibility of order 100 THz/strain for spin transitions, and propose an experiment where the SiV spin is strongly coupled to a nanomechanical resonator.

Strain Engineering of the Silicon-Vacancy Center in Diamond: A Formal Overview

The paper "Strain engineering of the silicon-vacancy center in diamond" addresses the utilization of strain to manipulate the electronic structure of silicon-vacancy (SiV) color centers in diamond. This research leverages nano-electro-mechanical systems (NEMS) to facilitate deterministic tuning of the properties of these centers, offering potential advancements in the development of scalable quantum networks.

Core Contributions

1. Strain-Induced Modulation of Electronic States: The paper demonstrates the capacity to control the optical and spin transition frequencies of SiV centers by modulating their local static strain environment. Through NEMS, hundreds of gigahertz of tuning for optical transitions are achieved, paving the way for spectral alignment of emitters crucial for photon-mediated entanglement.
2. Characterization of Strain Response: By assessing different SiV orientations relative to the strain direction, the research elucidates the strain response of both ground-state (GS) and excited-state (ES) electronic configurations. The paper unveils strain susceptibilities of approximately 1 PHz/strain for orbital states and identifies high strain susceptibility regimes for spin transitions—on the order of 100 THz/strain.
3. Strain Hamiltonian Analysis: The authors present a detailed strain Hamiltonian that explains the effects of shear and uniaxial strains. This framework successfully predicts the observed strain-tuning behavior, supported by fitting experimental data to theoretical models to estimate strain susceptibility parameters.

Numerical Results

• Optical Transition Tuning: The SiV centers exhibit tuning capabilities well beyond typical inhomogeneities of optical transition frequencies, specifically achieving a C transition wavelength shift of 150 GHz.
• Spin Transition Frequencies: Analyzing spin transitions under varying strain conditions, the researchers reveal significant sensitivity of spin states to strain perturbations, offering potential pathways for robust spin control.

Implications and Future Directions

The findings underscore the potential of SiV centers in strain-engineered configurations as a platform for quantum computing and communication. The ability to precisely tune optical emissions and spin states makes them suitable candidates for scalable quantum networks with consistent qubit-photon interfaces.

• Quantum Information Processing: The work suggests the feasibility of exploiting high strain susceptibilities for enhanced spin-phonon interactions. This could lead to strong coupling with nanomechanical resonators, drawing parallels to ion-trap quantum gates and facilitating phonon-mediated quantum operations.
• Practical Applications: The controlled emission characteristics support the development of tunable single-photon sources and integrated photonic circuits, aligning with broader quantum technology applications in secure communications and quantum simulations.

The research signals a compelling direction for ongoing studies in quantum materials and devices, indicating potential breakthroughs in the integration of quantum emitters and phononic interfaces. The paper provides a robust foundation for further experimental investigations, seeking to explore the complex interplay of strain, electronic structure, and quantum coherence in advanced material systems.