The ability to detect and distinguish quantum interference signatures is important for both fundamental research and for the realization of devices such as electron resonators¹, interferometers² and interference-based spin filters³. Consistent with the principles of subwavelength optics, the wave nature of electrons can give rise to various types of interference effects⁴, such as Fabry–Pérot resonances⁵, Fano resonances⁶ and the Aharonov–Bohm effect⁷. Quantum interference conductance oscillations⁸ have, indeed, been predicted for multiwall carbon nanotube shuttles and telescopes, and arise from atomic-scale displacements between the inner and outer tubes^9,10. Previous theoretical work on graphene bilayers indicates that these systems may display similar interference features as a function of the relative position of the two sheets^11,12. Experimental verification is, however, still lacking. Graphene nanoconstrictions represent an ideal model system to study quantum transport phenomena^13–15 due to the electronic coherence¹⁶ and the transverse confinement of the carriers¹⁷. Here, we demonstrate the fabrication of bowtie-shaped nanoconstrictions with mechanically controlled break junctions made from a single layer of graphene. Their electrical conductance displays pronounced oscillations at room temperature, with amplitudes that modulate over an order of magnitude as a function of subnanometre displacements. Surprisingly, the oscillations exhibit a period larger than the graphene lattice constant. Charge-transport calculations show that the periodicity originates from a combination of the quantum interference and lattice commensuration effects of two graphene layers that slide across each other. Our results provide direct experimental observation of a Fabry–Pérot-like interference of electron waves that are partially reflected and/or transmitted at the edges of the graphene bilayer overlap region.

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Spin-crossover (SCO) molecules are versatile magnetic switches with applications in molecular electronics and spintronics. Downscaling devices to the single-molecule level remains, however, a challenging task since the switching mechanism in bulk is mediated by cooperative intermolecular interactions. Here, we report on electron transport through individual Fe-SCO molecules coupled to few-layer graphene electrodes via π-π stacking. We observe a distinct bistability in the conductance of the molecule and a careful comparison with density functional theory (DFT) calculations allows to associate the bistability with a SCO-induced orbital reconfiguration of the molecule. We find long spin-state lifetimes that are caused by the specific coordination of the magnetic core and the absence of intermolecular interactions according to our calculations. In contrast with bulk samples, the SCO transition is not triggered by temperature but induced by small perturbations in the molecule at any temperature. We propose plausible mechanisms that could trigger the SCO at the single-molecule level.

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We analyse the electrical response of narrow graphene nanogaps in search for transport signatures stemming from spin-polarized edge states. We find that the electrical transport across graphene nanogaps having perfectly defined zigzag edges does not carry any spin-related signature. We also analyse the magnetic and electrical properties of nanogaps whose electrodes have wedges that possibly occur in the currently fabricated nanogaps. These wedges can host spin polarized wedge low-energy states due to the bipartite nature of the graphene lattice. We find that these spin-polarized low-energy modes give rise to low-voltage signatures in the differential conductance and to distinctive features in the stability diagrams. These are caused by fully spin-polarized currents.@en

This paper investigates the viability of the integration of demand side response of large scale electrolyser facilities into electrical ancillary services markets. A review of the current structure and mechanisms of balancing markets, voltage control and congestion management in the Netherlands is presented, taking into consideration future market harmonization measures proposed by transmission system operators of central Europe. The conducted research includes the assessment of the technical adequacy of electrolysers with respect to existing prequalification requirements, as well as basic notions on the expected revenue from participation in these markets. Furthermore, to illustrate the value of electrolyser support for electrical networks, a case study derived from the predicted Groningen-Drenthe-Overijssel area for the year 2030 is developed. This section of the northern Dutch transmission grid includes the upcoming HVDC interconnection with Denmark (COBRAcable) and one of the largest offshore wind parks located in the North Sea (Gemini). Computer based simulations are performed with DIgSILENT PowerFactory. The obtained results highlight the potential benefits of electrolyser utilization@en

This paper provides a review on emerging developments and challenges for provision of ancillary services by means of distributed generation, electrical and non-electrical demand side response and storage in the context of multi-energy conversion systems. To illustrate the value of demand side response as part of multi-energy sector coupling, a case study is built upon a three-area system, which includes conventional and renewable power plants as well as power to gas conversion system with electrolysers. Computer based simulations are performed by using PowerFactory platform to investigate the impact of the response of the electrolysers on power system operation. The results show that positive impacts on steady state and dynamic performances can be achieved by contributing to reduce the system stress. The extent of the contribution depends on the location, activation time, rating, and size of demand side associated to the electrolyser.@en