Defect states in monolayer hexagonal BN: A comparative DFT and DFT-1/2 study

Korkmaz, Yağmur Aksu; Bulutay, Ceyhun; Sevik, Cem

doi:10.1016/j.physb.2019.411959

Cited by 5 publications

(2 citation statements)

References 67 publications

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“…Even CVD-grown MLs, featuring large homogeneous domains, display emitters at a wavelength of 575 ± 15 nm, with no need for ion irradiation or annealing in argon [156]. The presence of carbon during other growth techniques (metallorganic vapour phase epitaxy and molecular beam epitaxy) appears to be crucial for the appearance of SPEs (as shown in figure 3(a)), with the V B C − N defect as a possible candidate [157], confirming several theoretical studies on the role of carbon [158][159][160][161][162][163][164][165][166][167], which also attributed the UV emission at 4.1 eV to the carbon dimer defect C B C N [168]. Control over the emitters wavelength has been partially achieved (i) via the Stark effect, tuning the emission with an out-of-plane electric field applied by graphene gates [169]; (ii) with a four-electrode device controlling both the amplitude and the direction of the electric field, leading to a Stark shift (visible in figure 3(b)) four times larger than the full width at half maximum (FWHM) at RT [170]; or (iii) by placing the emitters between an indium tin oxide coated glass slide and a conductive AFM tip [171].…”

Section: Hbnsupporting

confidence: 71%

One (photon), two(-dimensional crystals), a lot (of potential): a quick snapshot of a rapidly evolving field

Cianci,

Blundo,

Felici

2024

Nano Futures

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We present a concise overview of the state of affairs in the development of single-photon sources based on two-dimensional (2D) crystals, focusing in particular on transition-metal dichalcogenides and hexagonal boron nitride. We briefly discuss the current level of advancement (i) in our understanding of the microscopic origin of the quantum emitters (QEs) identified in these two material systems, and (ii) in the characterization of the optical properties of these emitters; then, we survey the main methods developed to enable the dynamic control of the QEs' emission energy. Finally, we summarize the main results stemming from the coupling of QEs embedded in 2D materials with photonic and plasmonic structures.

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Section: Hbnsupporting

confidence: 71%

One (photon), two(-dimensional crystals), a lot (of potential): a quick snapshot of a rapidly evolving field

Cianci,

Blundo,

Felici

2024

Nano Futures

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“…The efficiency is several orders of magnitude higher than using GW quasi-particle energies. Korkmaz et al [285] investigated the defects in monolayer hexagonal BN using LDA/GGA as well as DFT-1/2, including carbon impurities substituting for B or N, nitrogen vacancies as well as Stone-Wales defects. The carbon self-energy potential was from mixed −1/4s and −1/4p, thus pointing to −1/2 e charge stripping, in consistent with previous works and arguments [16,17,133].…”

Section: Defect Calculationsmentioning

confidence: 99%

DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity

Mao

Yan

Xue

et al. 2022

J. Phys.: Condens. Matter

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It is known that the Kohn-Sham eigenvalues do not characterize experimental excitation energies directly, and the band gap of a semiconductor is typically underestimated by local density approximation (LDA) of density functional theory (DFT). An embarrassing situation is that one usually uses LDA+U for strongly correlated materials with rectified band gaps, but for non-strongly-correlated semiconductors one has to resort to expensive methods like hybrid functionals or GW. In spite of the state-of-the-art meta-GGA functionals like TB09 and SCAN, methods with LDA-level complexity to rectify the semiconductor band gaps are in high demand. DFT-1/2 stands as a feasible approach and has been more widely used in recent years. In this work we give a detailed derivation of the Slater half occupation technique, and review the assumptions made by DFT-1/2 in semiconductor band structure calculations. In particular, the self-energy potential approach is verified through mathematical derivations. The aims, features and principles of shell DFT-1/2 for covalent semiconductors are also accounted for in great detail. Other developments of DFT-1/2 including conduction band correction, DFT+A-1/2, empirical formula for the self-energy potential cutoff radius, etc., are further reviewed. The relations of DFT-1/2 to hybrid functional, sX-LDA, GW, self-interaction correction, scissor’s operator as well as DFT+U are explained. Applications, issues and limitations of DFT-1/2 are comprehensively included in this review.

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Sliding Memristor in Parallel‐Stacked Hexagonal Boron Nitride

Du,

Yang,

Gao

et al. 2024

Advanced Materials

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Sliding ferroelectricity in 2D materials, arising from interlayer sliding‐induced interlayer hybridization and charge redistribution at the van der Waals interface, offers a means to manipulate spontaneous polarization at the atomic scale through various methods such as stacking order, interfacial contact, and electric field. However, the practical application of extending 2D sliding ferroelectricity remains challenging due to the contentious mechanisms and the complex device structures required for ferroelectric switching. Here, a sliding memristor based on a graphene/parallel‐stacked hexagonal boron nitride/graphene tunneling device, featuring a stable memristive hysteresis induced by interfacial polarizations and barrier height modulations, is presented. As the tunneling current density increases, the memristive window broadens, achieving an on/off ratio of ≈103 and 2 order decrease of the trigger current density, attributed to the interlayer migration of positively charged boron ions and the formation of conductive filaments, as supported by the theoretical calculations. The findings open a path for exploring the sliding memristor via a tunneling device and bridge the gap between sliding ferroelectricity and memory applications.

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Defect states in monolayer hexagonal BN: A comparative DFT and DFT-1/2 study

Cited by 5 publications

References 67 publications

One (photon), two(-dimensional crystals), a lot (of potential): a quick snapshot of a rapidly evolving field

One (photon), two(-dimensional crystals), a lot (of potential): a quick snapshot of a rapidly evolving field

DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity

Sliding Memristor in Parallel‐Stacked Hexagonal Boron Nitride

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