Interfacial engineering of ferromagnetism in wafer-scale van der Waals Fe4GeTe2 far above room temperature.

Despite recent advances in exfoliated vdW ferromagnets, the widespread application of 2D magnetism requires a Curie temperature (Tc) above room temperature as well as a stable and controllable magnetic anisotropy. Here we demonstrate a large-scale iron-based vdW material Fe4GeTe2 with the Tc reaching ~530 K. We confirmed the high-temperature ferromagnetism by multiple characterizations. Theoretical calculations suggested that the interface-induced right shift of the localized states for unpaired Fe d electrons is the reason for the enhanced Tc, which was confirmed by ultraviolet photoelectron spectroscopy. Moreover, by precisely tailoring Fe concentration we achieved arbitrary control of magnetic anisotropy between out-of-plane and in-plane without inducing any phase disorders. Our finding sheds light on the high potential of Fe4GeTe2 in spintronics, which may open opportunities for room-temperature application of all-vdW spintronic devices.

Tuning the Kondo resonance in two-dimensional lattices of cerium molecular complexes.

Cerium intermetallics have raised a lot of interest for the past forty years thanks to their very unusual and interesting electronic and magnetic properties. This can be explained by the peculiar electronic configuration of Ce (4f1) that allows different oxidation states leading to singular behavior such as quantum phase transitions, heavy-fermion behavior and the Kondo effect. In this work, we used a mixed-valence molecular analogue to study the Kondo effect down to the atomic scale by means of scanning tunneling microscopy/spectroscopy (STM/STS) for which new many-body effects are expected to emerge due to reduced dimensionality and specific chemical environment of the 4f-ion. For that purpose, double-decker molecular complexes hosting a Ce ion were synthesized and adsorbed onto Ag and Cu (111) surfaces forming two-dimensional lattices. As a result, we observed a zero-bias conductance resonance on Ag only indicative of a Kondo effect arising from the coupling between a molecular spin and the conducting electrons of the metallic surface. The emergence of the Kondo effect is discussed in terms of intermolecular and molecule/substrate interactions. This work expands the little knowledge to date on the structural and related electronic properties of Ce-based molecular systems on surfaces. In particular, it shows that Ce-based double deckers are good platforms to obtain insight into 4f-induced many-body effects down to the nanometer scale and in two-dimensional lattices. Moreover, this outcome has a strong impact for future applications of molecular devices in which both metals are commonly used as electrical contacts.

Quasi one-dimensional band dispersion and surface metallization in long-range ordered polymeric wires.

On-surface covalent self-assembly of organic molecules is a very promising bottom-up approach for producing atomically controlled nanostructures. Due to their highly tuneable properties, these structures may be used as building blocks in electronic carbon-based molecular devices. Following this idea, here we report on the electronic structure of an ordered array of poly(para-phenylene) nanowires produced by surface-catalysed dehalogenative reaction. By scanning tunnelling spectroscopy we follow the quantization of unoccupied molecular states as a function of oligomer length, with Fermi level crossing observed for long chains. Angle-resolved photoelectron spectroscopy reveals a quasi-1D valence band as well as a direct gap of 1.15 eV, as the conduction band is partially filled through adsorption on the surface. Tight-binding modelling and ab initio density functional theory calculations lead to a full description of the band structure, including the gap size and charge transfer mechanisms, highlighting a strong substrate-molecule interaction that drives the system into a metallic behaviour.

Reassessing the Aurignacian of Slovenia: techno-economic behaviour and direct dating of osseous projectile points.

The Palaeolithic of southern Central Europe has a long history of archaeological research. Particularly, the presence of numerous osseous projectile points in many early Upper Palaeolithic (EUP) assemblages in this region has attracted the attention of the international research community. However, the scarcity of properly identified and well-dated Aurignacian contexts represents an obstacle for investigation of the nature and timing of the Middle to Upper Palaeolithic transition. In this context, the question of whether Neandertals made Aurignacian osseous projectile points, either on their own or as a consequence of cultural interaction with anatomically modern humans (AMH), still remains an open issue. Here we reassess the EUP record of Slovenia by evaluating the Aurignacian character of the assemblages from Potocka zijalka, Mokriska jama and Divje babe I in the light of their suggested roots in the local Mousterian. We provide a comprehensive description of the lithic industry from Potocka zijalka, which represents one of the rare EUP assemblages of southern Central Europe with a representative number of lithic artefacts to be analysed from the perspective of lithic technology and raw material economy. Our re-analysis of the Slovenian assemblages is backed by a series of 11 new ultrafiltered collagen 14C dates obtained directly on associated osseous projectile points from the studied assemblages. The Aurignacian of Potocka zijalka underlines the remarkable consistency of the Early Aurignacian with low typo-technological variability across Europe, resulting from a marked dependence on transported toolkits and raw material conservation. The new radiocarbon determinations for the Aurignacian of Slovenia appear to post-date the 34-32 ka BP (thousands of years before present) threshold for the last Neandertals in the region. Although not falsified, the hypothesis of Aurignacian bone tools in southern Central Europe as a product of late Neandertals is not supported by our re-examination of the EUP record of Slovenia.

PROTICdb: a web-based application to store, track, query, and compare plant proteome data.

PROTICdb is a web-based application, mainly designed to store and analyze plant proteome data obtained by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and mass spectrometry (MS). The purposes of PROTICdb are (i) to store, track, and query information related to proteomic experiments, i.e., from tissue sampling to protein identification and quantitative measurements, and (ii) to integrate information from the user's own expertise and other sources into a knowledge base, used to support data interpretation (e.g., for the determination of allelic variants or products of post-translational modifications). Data insertion into the relational database of PROTICdb is achieved either by uploading outputs of image analysis and MS identification software, or by filling web forms. 2-D PAGE annotated maps can be displayed, queried, and compared through a graphical interface. Links to external databases are also available. Quantitative data can be easily exported in a tabulated format for statistical analyses. PROTICdb is based on the Oracle or the PostgreSQL Database Management System and is freely available upon request at the following URL: http://moulon.inra.fr/ bioinfo/PROTICdb.

The semantic smart laboratory: a system for supporting the chemical eScientist.

One goal of eScience is to enable the end-to-end publication of experiments and results. In the Combechem project we have developed an innovative human-centred system which captures the process of a chemistry experiment from plan to execution. The system comprises an electronic lab book replacement, which has been successfully trialled in a synthetic organic chemistry laboratory, and a flexible back-end storage system. Working closely with the users, we found that a light touch and a high degree of flexibility was required in the user interface. In this paper, we concentrate on the representation and storage of human-scale experiment metadata, introducing an ontology to describe the record of an experiment, and a storage system for the data from our lab book software. Just as the interfaces need to be flexible to cope with whatever a chemist wishes to record, so the back end solutions need to be similarly flexible to store any metadata that may be created. The storage system is based on Semantic Web technologies, such as RDF, and Web Services. It gives a much higher degree of flexibility to the type of metadata it can store, compared to the use of rigid relational databases.

Balancing at the border of instability.

Some biological systems operate at the critical point between stability and instability, and this requires a fine tuning of parameters. We bring together two examples from the literature that illustrate this: neural integration in the nervous system and hair cell oscillations in the auditory system. In both examples the question arises as to how the required fine tuning may be achieved and maintained in a robust and reliable way. We study this question using tools from nonlinear and adaptive control theory. We illustrate our approach on a simple model which captures some of the essential features of neural integration. As a result, we propose a large class of feedback adaptation rules that may be responsible for the experimentally observed robustness of neural integration. We mention extensions of our approach to the case of hair cell oscillations in the ear.