In the next 20 years, the fossil energy must become a guarantor of the sustainable de- velopment of the energy sector for future generations. Significant threats represent hurdles in this transition. This study identified current global trends in the energy sector and the prospects for the development of energy until 2035. The importance of risk assessment in scenario forecasting based on expert judgments was proven. Three contrasting scenarios, #StayHome, #StayAlone, and #StayEffective, for the development of fossil energy, all based on comprehensive analysis of global risks by expert survey and factor analysis, were developed. It was concluded that fossil energy is mandatory with integration of advanced technologies at every stage of the production of traditional energy and of renewable energy as an integral part of the modern energy sector. Based on the results of the study, nine ambitious programs for the development of sustainable energy are presented. They require the creation and the utilization of a single interactive digital platform adapted to this purpose. It is a passport mandatory for the flexible interaction of energy production, its transmission, and its consumption in the perspective of having a future sustainable, reliable, and secured energy sector.

This work demonstrates the magnetic field-induced spectral properties of metamaterials incorporating both indium antimonide (InSb) and tungsten (W) in the terahertz (THz) frequency regime. Nanostructure materials, layer thicknesses and surface grating fill factors are modified, impacting light-matter interactions and consequently modifying thermal emission. We describe and validate a method for determining spectral properties of InSb under an applied direct current (DC) magnetic field, and employ this method to analyze how these properties can be tuned by modulating the field magnitude. Notably, an InSb-W metamaterial exhibiting unity narrowband emission is designed, suitable as an emitter for wavelengths around 55 µm (approximately 5.5 THz), which is magnetically tunable in bandwidth and peak wavelength.

We will discuss recent results: (i) on the Casimir torque between two metallic one-dimensionalgratings rotated by an angle θ with respect to each other; and (ii) on the Casimir force occurring between interpenetrating gratings. These findings pave the way to the design of acontactless quantum vacuum torsional spring, and sensors with possible relevance to microand nanomechanical devices.

The nitrogen-vacancy (NV) defect in diamond is an efficient quantum sensor of randomly fluctuating signalsvia relaxometry measurements. In particular, the longitudinal spin relaxation of the NV defect accelerates in thepresence of magnetic noise with a spectral component at its electron spin resonance frequency.We look into thiseffect quantitatively by applying a calibrated and tunable magnetic noise on a single NV defect.We show that anincrease of the longitudinal spin relaxation rate translates into a reduction of the photoluminescence (PL) signalemitted under continuous optical illumination, which can be explained using a simplified three-level model of theNV defect. This PL quenching mechanism offers a simple, all-optical method to detect magnetic noise sourcesat the nanoscale.

The highest quality hexagonal boron nitride (hBN) crystals are grown from molten solutions. For hBN crystal growth at atmospheric pressure, typically the solvent is a combination of two metals, one with a high boron solubility and the other to promote nitrogen solubility. In this study, we demonstrate that high-quality hBN crystals can be grown at atmospheric pressure using pure iron as a flux. The ability to produce excellent-quality hBN crystals using pure iron as a solvent is unexpected, given its low solubility for nitrogen. The properties of crystals produced with this flux matched the best values ever reported for hBN: a narrow Raman E2g vibration peak (7.6 cm–1) and strong phonon-assisted peaks in the photoluminescence spectra. To further test their quality, the hBN crytals were used as a substrate for WSe2 epitaxy. WSe2 was deposited with a low nucleation density, indicating the low defect density of the hBN. Lastly, the carrier tunneling through our hBN thin layers (3.5 nm) follows the Fowler–Nordheim model, with a barrier height of 3.7 eV, demonstrating hBN’s superior electrical insulating properties. This ability to produce high-quality hBN crystals in such a simple, environmentally friendly and economical process will advance two-dimensional material research by enabling integrated devices.

Les méthodes expérimentales permettant de détecter la résonance de spin électronique de défauts ponctuels du diamant ouvrent de nouvelles perspectives pour le développement de capteurs quantiques à haute sensibilité. De tels capteurs ont notamment démontré des performances exceptionnelles pour l’imagerie magnétique aux échelles nanométriques, conduisant à une transition accélérée vers des solutions commerciales.

We report a study of polymorphic boron nitride samples. We interpret the photoluminescence line at 6.032±0.005 eV, that can be recorded at 8K in sp2-bonded boron nitride, as being the signature of the excitonic fundamental bandgap of the Bernal (or graphitic) boron nitride polymorph (bBN). This is determined by advanced photoluminescence measurements combined with x-ray characterizations on pure hexagonal boron nitride (hBN) and on polymorphic crystal samples, later compared with the theoretical predictions of Lorenzo Sponza, et al., Physical Review B 98, 125206 (2018). The overall picture is consistent with a direct excitonic fundamental bandgap of the Bernal (or graphitic) polymorph of boron nitride. This value dXb = 6.032±0.005 eV is higher than the indirect bandgap of hBN (iXh =5.955±0.005 eV).