Excitons in boron nitride single layer

Galvani, Thomas; Paleari, Fulvio; Miranda, Henrique; Molina-Sánchez, Alejandro; Wirtz, Ludger; Latil, Sylvain; Amara, Hakim; Ducastelle, F.

doi:10.1103/physrevb.94.125303

Cited by 87 publications

(153 citation statements)

References 64 publications

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“…As a benchmark, the GW band structure and optical spectrum of monolayer BN are also calculated (see Fig. S13 in the Supporting Materials), which is in good agreement with the previous calculations [48,49].…”

Section: Stability Of Ordered (Bn)1−x(c2)x Alloyssupporting

confidence: 84%

Giant enhancement of solid solubility in monolayer alloys by selective orbital coupling

Wang

Kang

et al. 2020

Phys. Rev. B

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Solid solubility (SS) is one of the most important features of alloys, which is usually difficult to be largely tuned in the entire alloy concentrations by external approaches. Some alloys that were supposed to have promising physical properties could turn out to be much less useful because of their poor SS, e.g., the case for monolayer BNC [(BN)1−x(C2)x] alloys. Until now, an effective approach on significantly enhancing SS of (BN)1−x(C2)x in the entire x is still lacking. In this article, a novel mechanism of selective orbital coupling between high energy wrong-bond states and surface states mediated by the specific substrate has been proposed to stabilize the wrong-bonds and in turn significantly enhance the SS of (BN)1−x(C2)x alloys. Surprisingly, we demonstrate that five ordered alloys, exhibiting variable direct quasi-particle bandgaps from 1.35 to 3.99 eV, can spontaneously be formed at different x when (BN)1−x(C2)x is grown on hcp-phase Cr. Interestingly, the optical transitions around the band edges in these ordered alloys, accompanied by largely tunable exciton binding energies of ~1 eV at different x, are significantly strong due to their unique band structures. Importantly, the disordered (BN)1−x(C2)x alloys, exhibiting fully tunable bandgaps from 0 to ~6 eV in the entire x, can be formed on Cr substrate at the miscibility temperature of ~1200 K, which is greatly reduced compared to that of 4500~5600 K in free-standing form or on other substrates. Our discovery not only may resolve the long-standing SS problem of BNC alloys, but also could significantly extend the applications of BNC alloys for various optoelectronic applications.

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Section: Stability Of Ordered (Bn)1−x(c2)x Alloyssupporting

confidence: 84%

Giant enhancement of solid solubility in monolayer alloys by selective orbital coupling

Wang

Kang

et al. 2020

Phys. Rev. B

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“…The work of Ref. 33 has also studied the excitonic states. Their results are in good agreement with the ones obtained from this work.…”

Section: Width Of Bands [Ev]mentioning

confidence: 99%

Excitons in hexagonal boron nitride single-layer: a new platform for polaritonics in the ultraviolet

et al. 2019

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The electronic and optical properties of 2D hexagonal boron nitride are studied using first principle calculations. GW and BSE methods are employed in order to predict with better accuracy the excited and excitonic properties of this material. We determine the values of the band gap, optical gap, excitonic binding energies and analyse the excitonic wave functions. We also calculate the exciton energies following an equation of motion formalism and the Elliot formula, and find a very good agreement with the GW +BSE method. The optical properties are studied for both the TM and TE modes, showing that 2D hBN is a good candidate to polaritonics in the UV range. In particular it is shown that a single layer of h-BN can act as an almost perfect mirror for ultraviolet electromagnetic radiation. arXiv:1807.06413v1 [cond-mat.mes-hall]

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“…In the case of h-BN the conduction states at low energy are concentrated on the boron atoms, more precisely on their π states pointing along the hexagonal axis [16], so that, finally, within the dipolar approximation, we have to calculate the dipolar matrix element π |q · r|1s . Because of the symmetry of the π state, only the component of r along the hexagonal axis survives, so that we expect that…”

Section: A Core Losses At the Boron K Edgementioning

confidence: 99%

Angle-resolved electron energy loss spectroscopy in hexagonal boron nitride

et al. 2017

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Electron energy loss spectra were measured on hexagonal boron nitride single crystals employing an electron energy loss spectroscopic setup composed of an electron microscope equipped with a monochromator and an in-column filter. This setup provides high-quality energy-loss spectra and allows also for the imaging of energy-filtered diffraction patterns. These two acquisition modes provide complementary pieces of information, offering a global view of excitations in reciprocal space. As an example of the capabilities of the method we show how easily the core loss spectra at the K edges of boron and nitrogen can be measured and imaged. Low losses associated with interband and/or plasmon excitations are also measured. This energy range allows us to illustrate that our method provides results whose quality is comparable to that obtained from nonresonant x-ray inelastic scattering but with advantageous specificities such as an enhanced sensitivity at low q and a much greater simplicity and versatility that make it well adapted to the study of two-dimensional materials and related heterostructures. Finally, by comparing theoretical calculations to our measures, we are able to relate the range of applicability of ab initio calculations to the anisotropy of the sample and assess the level of approximation required for a proper simulation of our acquisition method.

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Excitons in boron nitride single layer

Cited by 87 publications

References 64 publications

Giant enhancement of solid solubility in monolayer alloys by selective orbital coupling

Giant enhancement of solid solubility in monolayer alloys by selective orbital coupling

Excitons in hexagonal boron nitride single-layer: a new platform for polaritonics in the ultraviolet

Angle-resolved electron energy loss spectroscopy in hexagonal boron nitride

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