Stone–Wales defects in hexagonal boron nitride as ultraviolet emitters

Hamdi, H.; Thiering, Gergő; Bodrog, Zoltán; Ivády, Viktor; Gali, Ádám

doi:10.1038/s41524-020-00451-y

Cited by 38 publications

(31 citation statements)

References 43 publications

(71 reference statements)

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“…The C N O N pair has also been suggested to explain the 4.1 eV luminescence [24]. However, a stoichiometric Stone-Wales defect that does not involve carbon at all has also been recently proposed [25]. All these three defects are expected to emit in the UV, but the debate regarding the exact chemical nature of the 4.1 eV emitters seems to continue.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics of carbon point defects in hexagonal boron nitride

Maciaszek,

Razinkovas,

Alkauskas

2021

Preprint

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We present a first-principles computational study of the thermodynamics of carbon defects in hexagonal boron nitride (hBN). The defects considered are carbon monomers, dimers, trimers, and larger carbon clusters, as well as complexes of carbon with vacancies, antisites, and substitutional oxygen. Our calculations show that monomers (C B , C N ), dimers, trimers, and C N O N pairs are the most prevalent species under most growth conditions. Compared to these defects, complexes of carbon with vacancies and antisites occur at much smaller concentrations (<10 14 cm −3 ). Our results are discussed in view of the relevance of carbon defects in singlephoton emission in hBN.

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Section: Introductionmentioning

confidence: 99%

Thermodynamics of carbon point defects in hexagonal boron nitride

Maciaszek,

Razinkovas,

Alkauskas

2021

Preprint

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“…Examples include boron dangling bonds as source for single photon emission at 2.06 eV [41] which could explain the accumulation of emitters localized near crystal edges or grain boundaries [42,43]. UV emission at 4.08 eV was traced back to optically active, pentagon-hexagon Stone-Wales defects preferentially present in poly-crystalline h-BN [44]. Emitters with transition energies between 2.0 and 2.2 eV were also found to originate from carbonrelated defects [45].…”

Section: The Large Family Of Defect Centers In H-bnmentioning

confidence: 99%

Review on coherent quantum emitters in hexagonal boron nitride

Kubanek¹

2022

Preprint

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Hexagonal boron nitride is an emerging two-dimensional material with far-reaching applications in fields like nanophotonics or nanomechanics. Its layered architecture plays a key role for new materials such as Van der Waals heterostructures. The layered structure has also unique implications for hosted, optically active defect centers. A very special type of defect center arises from the possibility to host mechanically isolated orbitals localized between the layers. The resulting absence of coupling to low-frequency acoustic phonons turns out to be the essential element to protect the coherence of optical transitions from mechanical interactions with the environment. Consequently, the spectral transition linewidth remains unusually narrow even at room temperature, thus paving a new way towards coherent quantum optics under ambient conditions. In this review, I summarize the state-of-the-art of defect centers in hexagonal boron nitride with a focus on optically coherent defect centers. I discuss the current understanding of the defect centers, remaining questions and potential research directions to overcome pervasive challenges. The field is put into a broad perspective with impact on quantum technology such as quantum optics, quantum photonics as well as spin optomechanics.

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“…S3 of the SI). In addition, in the case of defect systems with singlet GS and ES, we expect non-negligible differences between TDDFT and CDFT results, since the accurate description of a singlet ES requires a linear combination of at least two Slater determinants [14,69]. In that case the use of quantum embedding theories (QDET), should be preferable to describe strongly correlated states [70][71][72].…”

Section: A Zero-phonon Linesmentioning

confidence: 99%

“…As for many properties of condensed systems, Density Functional Theory (DFT) has turned out to be a valuable tool to compute PL spectra, which are used to interpret experiments as well as to provide predictions of the fingerprints of specific defects in materials [7][8][9]. For example, first principles spectra based on DFT have been recently reported for nitrides, e.g., GaN [10,11], AlN [12], and hexagonal born nitride (h-BN) [13][14][15][16][17][18], diamond [19][20][21][22][23][24][25][26][27][28][29], silicon carbide (SiC) [30][31][32][33], and monolayers of transition metal dichalcogenides (TMDC) [34]. These studies have been performed with several useful computational approaches; however, a systematic assessment of the theoretical and numerical approximations adopted in PL calculations has not yet been conducted.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence spectra of point defects in semiconductors: validation of first principles calculations

Jin,

Govoni,

Wolfowicz

et al. 2021

Preprint

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Optically and magnetically active point defects in semiconductors are interesting platforms for the development of solid-state quantum technologies. Their optical properties are usually probed by measuring photoluminescence spectra, which provide information on excitation energies and on the interaction of electrons with lattice vibrations. We present a combined computational and experimental study of photoluminescence spectra of defects in diamond and SiC, aimed at assessing the validity of theoretical and numerical approximations used in first principles calculations, including the use of the Franck-Condon principle and the displaced harmonic oscillator approximation. We focus on prototypical examples of solid-state qubits, the divacancy centers in SiC and the nitrogen-vacancy in diamond, and we report computed photoluminescence spectra as a function of temperature that are in very good agreement with the measured ones. As expected we find that the use of hybrid functionals leads to more accurate results than semilocal functionals. Interestingly our calculations show that constrained density functional theory (CDFT) and time-dependent hybrid DFT perform equally well in describing the excited state potential energy surface of triplet states; our findings indicate that CDFT, a relatively cheap computational approach, is sufficiently accurate for the calculations of photoluminescence spectra of the defects studied here. Finally, we find that only by correcting for finite-size effects and extrapolating to the dilute limit, one can obtain a good agreement between theory and experiment. Our results provide a detailed validation protocol of first principles calculations of photoluminescence spectra, necessary both for the interpretation of experiments and for robust predictions of the electronic properties of point defects in semiconductors.I.

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Stone–Wales defects in hexagonal boron nitride as ultraviolet emitters

Cited by 38 publications

References 43 publications

Thermodynamics of carbon point defects in hexagonal boron nitride

Thermodynamics of carbon point defects in hexagonal boron nitride

Review on coherent quantum emitters in hexagonal boron nitride

Photoluminescence spectra of point defects in semiconductors: validation of first principles calculations

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