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Midgap state requirements for optically active quantum defects

MetadataDetails
Publication Date2024-01-10
JournalMaterials for Quantum Technology
AuthorsYihuang Xiong, Milena Mathew, Sinéad M. Griffin, Alp Sipahigil, Geoffroy Hautier
InstitutionsUniversity of California, Berkeley, Dartmouth College
Citations12

Abstract Optically active quantum defects play an important role in quantum sensing, computing and communication. The electronic structure and the single-particle energy levels of these quantum defects in the semiconducting host have been used to understand their optoelectronic properties. Optical excitations that are central for their initialization and readout are linked to transitions between occupied and unoccupied single-particle states. It is commonly assumed that only quantum defects introducing levels well within the band gap and far from the band edges are of interest for quantum technologies as they mimic an isolated atom embedded in the host. In this perspective, we contradict this common assumption and show that optically active defects with energy levels close to the band edges can display similar properties. We highlight quantum defects that are excited through transitions to or from a band-like level (bound exciton) such as the T center and Se <mml:math xmlns:mml=“http://www.w3.org/1998/Math/MathML” overflow=“scroll”> <mml:msubsup> <mml:mi/> <mml:mrow> <mml:mrow> <mml:mi mathvariant=“normal”>S</mml:mi> <mml:mi mathvariant=“normal”>i</mml:mi> </mml:mrow> </mml:mrow> <mml:mo>+</mml:mo> </mml:msubsup> </mml:math> in silicon. We also present how defects such as the silicon split-vacancy in diamond can involve transitions between localized levels that are above the conduction band or below the valence band. Loosening the commonly assumed requirement on the electronic structure of quantum defects offers opportunities in quantum defects design and discovery especially in smaller band gap hosts such as silicon. We discuss the challenges in terms of operating temperature for photoluminescence or radiative lifetime in this regime. We also highlight how these alternative type of defects bring their own needs in terms of theoretical developments and fundamental understanding. This perspective clarifies the electronic structure requirement for quantum defects and will facilitate the identification and design of new color centers for quantum applications especially driven by first principles computations.

  1. 2021 - Quantum guidelines for solid-state spin defects [Crossref]
  2. 2021 - Silicon photonic quantum computing with spin qubits [Crossref]
  3. 2018 - Material platforms for spin-based photonic quantum technologies [Crossref]
  4. 2020 - Integrated quantum photonics with silicon carbide: challenges and prospects [Crossref]
  5. 2020 - Silicon carbide color centers for quantum applications [Crossref]
  6. 2020 - Initialization and read-out of intrinsic spin defects in a van der waals crystal at room temperature [Crossref]
  7. 2019 - Carbon dimer defect as a source of the 4.1 eV luminescence in hexagonal boron nitride [Crossref]
  8. 2019 - Dangling bonds in hexagonal boron nitride as single-photon emitters [Crossref]
  9. 2008 - Multipartite entanglement among single spins in diamond [Crossref]