Explore the vast range of titles available.

Nitrogen-vacancy (NV) centers in diamond have become an important instrument for quantum sensing and quantum information science. However, the readout of NV spin state requires bulky optical setups, limiting fabrication of miniaturized compact devices for practical use. Here we realized photoelectrical detection of magnetic resonance as well as Rabi oscillations on a single-defect level. Furthermore, photoelectrical imaging of individual NV centers at room temperature was demonstrated, surpassing conventional optical readout methods by providing high imaging contrast and signal-to-noise ratio. These results pave the way toward fully integrated quantum diamond devices.

Nuclear spins in semiconductors are leading candidates for future quantum technologies, including quantum computation, communication, and sensing. Nuclear spins in diamond are particularly attractive due to their long coherence time. With the nitrogen-vacancy (NV) centre, such nuclear qubits benefit from an auxiliary electronic qubit, which, at cryogenic temperatures, enables probabilistic entanglement mediated optically by photonic links. Here, we demonstrate a concept of a microelectronic quantum device at ambient conditions using diamond as wide bandgap semiconductor. The basic quantum processor unit – a single 14 N nuclear spin coupled to the NV electron – is read photoelectrically and thus operates in a manner compatible with nanoscale electronics. The underlying theory provides the key ingredients for photoelectric quantum gate operations and readout of nuclear qubit registers. This demonstration is, therefore, a step towards diamond quantum devices with a readout area limited by inter-electrode distance rather than by the diffraction limit. Such scalability could enable the development of electronic quantum processors based on the dipolar interaction of spin-qubits placed at nanoscopic proximity. Nuclear spins in diamond are promising for applications in quantum technologies due to their long coherence times. Here, the authors demonstrate a scalable electrical readout of individual intrinsic 14 N nuclear spins in diamond, mediated by hyperfine coupling to electron spin of the NV center, as a step towards room-temperature nanoscale diamond quantum devices.

Cu(In,Ga)Se 2 -based solar cells have reached efficiencies close to 23%. Further knowledge-driven improvements require accurate determination of the material properties. Here, we present refractive indices for all layers in Cu(In,Ga)Se 2 solar cells with high efficiency. The optical bandgap of Cu(In,Ga)Se 2 does not depend on the Cu content in the explored composition range, while the absorption coefficient value is primarily determined by the Cu content. An expression for the absorption spectrum is proposed, with Ga and Cu compositions as parameters. This set of parameters allows accurate device simulations to understand remaining absorption and carrier collection losses and develop strategies to improve performances.

We propose the use of a diamond waveguide structure to enhance the sensitivity of magnetometers relying on the detection of the spin state of nitrogen-vacancy ensembles in diamond by infrared optical absorption. An optical waveguide structure allows for enhanced optical path-lengths avoiding the use of optical cavities and complicated setups. The presented design for diamond-based magnetometers enables miniaturization while maintaining high sensitivity and forms the basis for magnetic field sensors applicable in biomedical, industrial and space-related applications.

Cu(In,Ga)Se based solar cells have reached efficiencies close to 23%. Further knowledge-driven improvements require accurate determination of the material properties. Here, we present refractive indices for all layers in Cu(In,Ga)Se solar cells with high efficiency. The optical bandgap of Cu(In,Ga)Se does not depend on the Cu content in the explored composition range, while the absorption coefficient value is primarily determined by the Cu content. An expression for the absorption spectrum is proposed, with Ga and Cu compositions as parameters. This set of parameters allows accurate device simulations to understand remaining absorption and carrier collection losses and develop strategies to improve performances.

Summary This study was designed to assess the influence of three soil DNA extraction procedures, namely the International Organization for Standardization (ISO‐11063, GnS‐GII and modified ISO procedure (ISOm), on the taxonomic diversity and composition of soil bacterial and fungal communities. The efficacy of each soil DNA extraction method was assessed on five soils, differing in their physico‐chemical characteristics and land use. A meta‐barcoded pyrosequencing approach targeting 16S and 18S rRNA genes was applied to characterize soil microbial communities. We first observed that the GnS‐GII introduced some heterogeneity in bacterial composition between replicates. Then, although no major difference was observed between extraction procedures for soil bacterial diversity, we saw that the number of fungal genera could be underestimated by the ISO‐11063. In particular, this procedure underestimated the detection in several soils of the genera Cryptococcus, Pseudallescheria, Hypocrea and Plectosphaerella, which are of ecological interest. Based on these results, we recommend using the ISOm method for studies focusing on both the bacterial and fungal communities. Indeed, the ISOm procedure provides a better evaluation of bacterial and fungal communities and is limited to the modification of the mechanical lysis step of the existing ISO‐11063 standard. This study was designed to assess the influence of three soil DNA extraction procedures, namely the ISO‐11063, GnS‐GII, and ISOm, on the taxonomic diversity and composition of soil bacterial and fungal communities. The efficacy of each soil DNA extraction method was assessed on five soils, differing in their physico‐chemical characteristics and land use. In conclusion, we recommend using the ISOm method for studies focusing on both the bacterial and fungal communities.

Wastewater can be recycled in agricultural soil as fertilizer to increase crop yields. However, adding wastewater induces sometimes ecotoxicological issues such as pollution by toxic compounds, which may lead to the loss of arable land. Bioenergy crops such as Miscanthus × giganteus have been tested to rehabilitate polluted soils, but the impact of Miscanthus on soil microbes is unknown. Here, we evaluated the effects of Miscanthus cropping on bacterial and fungal taxonomic composition in a wastewater-contaminated soil using synchronic and diachronic evaluation strategies. A 3-year field experiment close to Paris was set up on an agricultural site irrigated by raw wastewater for more than one century, thus resulting in strong metal and organic contamination. Soil microbial taxonomic composition was characterized by direct analysis of soil DNA using metagenomic tools such as 454 pyrosequencing of ribosomal genes. Our results demonstrate that Miscanthus cropping stimulates specific populations of bacteria such as Rhizobiales, increased by 1.4 in relative abundance, Nistrospira (x1.5), Azospira (x2), and Gemmatimonas (x2), and fungi: Glomeromycota (x3) and Mortierella (x1.5) for fungi. Noteworthy, these microbial genera are known to be strongly involved in plant symbiosis, organic matter mineralization, and nutrient cycling. Overall our findings show that Miscanthus cropping enhances regeneration of soil microbiological functions and services in polluted soil by stimulating populations beneficial for soil fertility and crop production.

In France, about 90,000 ha per year of arable land become unsuitable for food production due to erosion, acidification, sealing and pollution by metallic and organic compounds. Bioenergy crops such as Miscanthus x giganteus are used to rehabilitate polluted soils for crop production. Although the economic potential of this crop is known, the crop abilities to regenerate the soil biological properties enabling sustainable crop production still remain unclear. Here, we evaluated the effects of the Miscanthus crop on the abundance and diversity of soil bacterial and fungal communities in a wastewater-contaminated soil, using synchronic and diachronic evaluation strategies. A 3-year field experiment, near Paris, was set up on an agricultural field irrigated with raw wastewater for more than 100 years, thus inducing a strong metal and organic contamination of the soil. We characterized the abundance and diversity of soil microbial communities using metagenomic techniques. Our results show that the Miscanthus crop had an early effect on microbial communities by stimulating bacterial diversity, by about 20 %, and fungal diversity, by about 10 %. This positive effect could be explained by the release of fresh organic matter from litter decomposition and root exudation, and by the absence of tillage and pesticide spraying, which are known to degrade soil microflora. On the other hand, no significant effect on microbial biomass has been recorded. Overall our findings show that Miscanthus cropping is a promising practice to enhance the regeneration of soil microbiological diversity and to reclame polluted soils.

We report on a mathematical model of the photoelectric response of NV colour centres in diamond, that can be employed for sensing and quantum science information applications. Although the model applies to NV centre in diamond, it can be applied with small modifications to other semiconducting solid state qubits. In our model, we include the drift and collection of charge carriers as well as the presence of other defects via generation and recombination dynamics. Though the photoluminescence readout and the associated dynamics of the NV defect has been extensively studied experimentally and theoretically, so far, there has been no precise model for photocurrent readout, including these effects. In our description, we use a multilevel-level system including mS=0, mS=+-1 ground and excited states, singlet state and the NV0 neutral state. Also, the presence of substitutional nitrogen (NS), which for example determines the spin coherence via the paramagnetic spin bath, is discussed together with presence of acceptor defects. We model the time-dependent occupation of all electronic sublevels and also consider the electronic charge transport from the Boltzmann transport equation, leading to information about the charge state transitions and recombination dynamics. ODMR and PDMR response as well as their quantum efficiencies, are calculated. On this basis, we determine an optimal parameter space for qubit operations, including the highest spin contrast and especially relate those to NS presence. The model is confirmed experimentally and can become a useful tool for optimisation of the performance of NV qubit photoelectric readout.

This study was designed to assess the influence of three soil DNA extraction procedures, namely the International Organization for Standardization (ISO‐11063, GnS‐GII and modified ISO procedure (ISOm), on the taxonomic diversity and composition of soil bacterial and fungal communities. The efficacy of each soil DNA extraction method was assessed on five soils, differing in their physico‐chemical characteristics and land use. A meta‐barcoded pyrosequencing approach targeting 16S and 18S rRNA genes was applied to characterize soil microbial communities. We first observed that the GnS‐GII introduced some heterogeneity in bacterial composition between replicates. Then, although no major difference was observed between extraction procedures for soil bacterial diversity, we saw that the number of fungal genera could be underestimated by the ISO‐11063. In particular, this procedure underestimated the detection in several soils of the genera Cryptococcus, Pseudallescheria, Hypocrea and Plectosphaerella, which are of ecological interest. Based on these results, we recommend using the ISOm method for studies focusing on both the bacterial and fungal communities. Indeed, the ISOm procedure provides a better evaluation of bacterial and fungal communities and is limited to the modification of the mechanical lysis step of the existing ISO‐11063 standard.