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The present paper introduces a new risk-informed based tool that can support disaster management authorities in making decisions in response to earthquakes at local and regional scales by using estimated physical and socio-economic losses. The risk-informed based tool is building upon existing risk assessment methods, and multi-criteria decision-making (MCDM) methodology. The integrated risk assessment methods are adapted from the earthquake loss estimation tool SELENA. The integrated MCDM methodology, allowing selection of optimal mitigation measures by taking into account the priorities and preferences of disaster management authorities, was developed within the EU Horizon 2020 TURNkey project [1]. The new tool presented in this study also allows easy integration and incorporation of existing database and models that can be openly available. The tool is characterized with user-friendly interface and flexible format of the input and output data, that can be easily understood by different actors in disaster risk management.

Blida (Algeria) is characterized by a high level of seismic exposure and vulnerability due to its dense population and the presence of aging buildings. The historical earthquake that occurred in 1825, with a moment magnitude (Mw7.1), underscored the urgent need for a thorough assessment of seismic risk in the area. Here, an extensive study conducted in downtown of the city of Blida to evaluate seismic risk and its consequences is presented. Geounits 141 and 148 emerged as the most severely affected in all the simulated earthquake scenarios indicating severe damage and casualties mainly for closest earthquakes (Blida and Bounaian, both with moment magnitude Mw7.1) but also for furthest earthquakes as Mouzaia El Affroun (Mw6.6), and Hammam Melouane (Mw.5). The sensitivity analysis demonstrated the importance of the selection of the performance point computation method (improved displacement coefficient method -IDCM, modified capacity spectrum-MADRS, and nonlinear analysis method-N2) and the choice of the ground motion prediction equation. IDCM results are less influenced by the choice of the GMPE, but they provide higher damage results expressed as a mean damage ratio. Moreover, the study estimated potential human impacts in the Blida region, highlighting varying levels of impact on different geounits under different earthquake scenarios. The study's primary findings from seismic risk assessments in the studied region highlight its high susceptibility to earthquakes and can be summarized as follows: The mean damage ratio will be 52.6% ± 1.4%, 50.9% ± 1.6%; 31.8% ± 3.4% and 21.4% ± 3.1% for the Blida, Bounaian, Mouzaia El Affroun and Hammam Melouane earthquakes respectively.

We investigate two novel models of charged black holes in the framework of non-linear electrodynamics of Born–Infeld type. In particular, starting from two concrete Lagrangian densities, the corresponding metric potentials, the electric field, the Smarr formula and finally, the (scalar) quasinormal modes are computed for each model. Our findings show that although the models look very similar, their quasinormal spectra are characterized by certain differences.

In this paper, we study the black hole spacetime structure of a model consisting of the standard Maxwell theory and a p-power-Yang-Mills term. This non-linear contribution introduces a non-Abelian charge into the global solution, resulting in a modified structure of the standard Reissner-Nordström black hole. Specifically, we focus on the model with p = 1/2, which gives rise to a new type of modified Reissner-Nordström black hole. For this class of black holes, we compute the event horizon, the innermost stable circular orbit, and the conditions to preserve the weak cosmic censorship conjecture. The latter condition sets a well-established relation between the electric and the Yang-Mills charges. As a first astrophysical implication, the accretion properties of spherical steady flows around this new modified Reissner-Nordström black hole are investigated in detail. Concretely, we compute the critical radius that establishes the condition for having stable transonic flow in terms of the local sound speed and the involved charges. Extensive numerical examples of how the Yang-Mills charge affects the accretion process of an isothermal fluid in comparison to the standard Reissner-Nordström and Schwarzschild black holes are displayed. Finally, analytical solutions in the fully relativistic regime, along with numerical computations, of the mass accretion rate for a polytropic fluid in terms of the electric and Yang-Mills charges are obtained. As a main result, the mass accretion rate efficiency is considerably improved, with respect to the standard Reissner-Nordström and Schwarzschild solutions, for negative values of the Yang-Mills charge.

The objective of the study is to quantify the effect of climate change on the climatic risks associated with droughts and diminished water resources in the eastern Iberian Peninsula. For this purpose, this work analyses the 70-year historical series (1952–2021) of daily rainfall data from 353 meteorological stations. They are located in a key recharge area of the hydrological system, the Sierra de Albarracín, where three important rivers originate, namely the Tagus, the Júcar and the Turia, as do several tributaries of the Guadiana and Ebro rivers. It analyses trends in: annual and seasonal rainfall volumes with specific studies about their intensity according to certain percentiles; the number of rainy days, dry spell duration (< 1 mm/day) and drought evolution with the Standardized Precipitation Evaporation Index. The most relevant results are: (1) the second 35 years of the study period (1987–2021) were notably drier than the first part (1952–1986), with smaller volumes and fewer days with recorded precipitation; (2) summer and winter were most affected by pluviometric decrease, with losses of >50% of rainfall volume at some stations; (3) moderate rainfall significantly reduced between the 50th and 95th percentiles, which were more important in the system's water recharge; (4) the stations with a negative precipitation trend predominated; (5) the medium- and long-term analyses (12 and 36 months) highlighted the drought situation in which the headwaters of the analyzed basins are immersed. The trend indicates that the situation will become critical.

We study photon orbits within (1＋2)-dimensional Einstein-power-Maxwell non-linear electrodynamics assuming a static and circularly symmetric background. An exact analytical solution to the null geodesic equations for light rays is obtained in terms of the Weierstraß function. We investigate in detail the impact of the photon energy, the electric charge of the black hole, and the integration constant (initial condition) on the shape of the orbits.

The spin and lattice dynamics of a ferromagnetic nanoparticle are studied via molecular dynamics and with semi-classical spin dynamics simulations where spin and lattice degrees of freedom are coupled via a dynamic uniaxial anisotropy term. We show that this model conserves total angular momentum, whereas spin and lattice angular momentum are not conserved. We carry out simulations of the Einstein–de Haas effect for a Fe nanocluster with more than 500 atoms that is free to rotate, using a modified version of the open-source spin-lattice dynamics code (SPILADY). We show that the rate of angular momentum transfer between spin and lattice is proportional to the strength of the magnetic anisotropy interaction. The addition of the anisotropy allows full spin-lattice relaxation to be achieved on previously reported timescales of ∼ 100 ps and for tight-binding magnetic anisotropy energies comparable to those of small Fe nanoclusters.

In order to investigate the long-term evolution of radiation-induced defects in the fission- and fusion-relevant material iron, we introduce cascade overlap effects into Object Kinetic Monte Carlo simulations. In addition to cascade overlap, we study the effect of introducing discrete C15 Laves phase clusters into the simulations. By applying either, none, or both of these effects we identify how they influence the evolution of the system. We find that both cascade overlap and C15 clusters affect the evolution of the radiation damage in different ways and on different time scales. Cascade overlap is found to reduce the number of Frenkel pairs. On the other hand, the explicit consideration of C15 Laves phase clusters increases the accumulation of defects at low dose. The results are compared to Molecular Dynamics simulation results under similar conditions.

In this work, we introduce the complexity factor in the context of self-gravitating fluid distributions for the case of black holes by employing the Newman–Penrose formalism. In particular, by working with spherically symmetric and static AdS black holes, we show that the complexity factor can be interpreted in a natural way at the event horizon. Specifically, a thermodynamic interpretation for the aforementioned complexity factor in terms of a pressure partially supporting a Van der Waals-like equation of state is given.

After evaporation of the organic solvents, benzene, toluene, and cyclohexane on gold substrates, Scanning Tunneling Microscope (STM) shows the presence of a remaining adsorbed layer. The different solvent molecules were individually observed at ambient conditions, and their electronic transport properties characterized through the STM in the Break Junction approach. The combination of both techniques reveals, on one hand, that solvents are not fully evaporated over the gold electrode and, secondly, characterize the electronic transport of the solvents in molecular electronics.

The M4F project brings together the fusion and fission materials communities working on the prediction of radiation damage production and evolution and its effects on the mechanical behaviour of irradiated ferritic/martensitic (F/M) steels. It is a multidisciplinary project in which several different experimental and computational materials science tools are integrated to understand and model the complex phenomena associated with the formation and evolution of irradiation induced defects and their effects on the macroscopic behaviour of the target materials. In particular the project focuses on two specific aspects: (1) To develop physical understanding and predictive models of the origin and consequences of localised deformation under irradiation in F/M steels; (2) To develop good practices and possibly advance towards the definition of protocols for the use of ion irradiation as a tool to evaluate radiation effects on materials. Nineteen modelling codes across different scales are being used and developed and an experimental validation programme based on the examination of materials irradiated with neutrons and ions is being carried out. The project enters now its 4th year and is close to delivering high-quality results. This paper overviews the work performed so far within the project, highlighting its impact for fission and fusion materials science.

Simulating the long-term evolution of temperature and magnetic fields in neutron stars is a major effort in astrophysics, having significant impact in several topics. A detailed evolutionary model requires, at the same time, the numerical solution of the heat diffusion equation, the use of appropriate numerical methods to control non-linear terms in the induction equation, and the local calculation of realistic microphysics coefficients. Here we present the latest extension of the magneto-thermal 2D code in which we have coupled the crustal evolution to the core evolution, including ambipolar diffusion. It has also gained in modularity, accuracy, and efficiency. We revise the most suitable numerical methods to accurately simulate magnetar-like magnetic fields, reproducing the Hall-driven magnetic discontinuities. From the point of view of computational performance, most of the load falls on the calculation of microphysics coefficients. To a lesser extent, the thermal evolution part is also computationally expensive because it requires large matrix inversions due to the use of an implicit method. We show two representative case studies: (i) a non-trivial multipolar configuration confined to the crust, displaying long-lived small-scale structures and discontinuities; and (ii) a preliminary study of ambipolar diffusion in normal matter. The latter acts on timescales that are too long to have relevant effects on the timescales of interest but sets the stage for future works where superfluid and superconductivity need to be included.

Prediction of material performance in fusion reactor environments relies on computational modelling, and will continue to do so until the first generation of fusion power plants come on line and allow long-term behaviour to be observed. In the meantime, the modelling is supported by experiments that attempt to replicate some aspects of the eventual operational conditions. In 2019, a group of leading experts met under the umbrella of the IEA to discuss the current position and ongoing challenges in modelling of fusion materials and how advanced experimental characterisation is aiding model improvement. This review draws from the discussions held during that workshop. Topics covering modelling of irradiation-induced defect production and fundamental properties, gas behaviour, clustering and segregation, defect evolution and interactions are discussed, as well as new and novel multiscale simulation approaches, and the latest efforts to link modelling to experiments through advanced observation and characterisation techniques.

In this work, motivated by the fact that higher dimensional theories predict the existence of black holes which differ from their four dimensional counterpart, we analyse the geodesics and black hole shadow cast by a general non-extremal five dimensional black hole. The system under consideration corresponds to the Chong–Cvetič–Lü–Pope (Chong et al., 2005), which has the Myers–Perry black hole as a limit.

A method based on object kinetic Monte Carlo that can account for segregation and precipitation in metallic alloys in the presence of both vacancies and self-interstitials is presented. Here the model has been applied specifically to FeCr alloys, but could be used for other alloys with proper parametrization. The model is based on the division of the simulation box into cells where only the local concentration of the alloy is considered and not the explicit location of each alloy atom, in a mean field type of approach. This concentration, together with those of neighboring cells, is used to bias defect migration taking into account the proper thermodynamics of the alloy at hand and the stiffness coefficient to include neighboring effects. The novelty of this implementation is, among other things, the explicit description of mixed pairs of point defects with the alloy element: vacancy-Cr (VCr) and self-interstitial-Cr (ICr) whenever necessary. This explicit description allows the temperature dependence of defect evolution to be correctly reproduced. In this paper we present the model in detail for the particular case of processes that take place in the presence of vacancies, to show the robustness and applicability of this method.

Under the challenge of growing a single bilayer of Bi oriented in the (111) crystallographic direction over amorphous substrates, we have studied different thicknesses of Bi thermally evaporated onto silicon oxide in order to shed light on the dominant atomic structures and their oxidation. We have employed atomic force microscope, X-ray diffraction, and scanning electron microscope approaches to demonstrate that Bi is crystalline and oriented in the (111) direction for thicknesses over 20 nm. Surprisingly, Raman spectroscopy indicates that the rhombohedral structure is preserved even for ultra-thin layers of Bi, down to nm. Moreover, the signals also reveal that bismuth films exposed to ambient conditions do not suffer major surface oxidation.

In the present work, we extend and generalize our previous work regarding the scale dependence applied to black holes in the presence of non-linear electrodynamics (Rincón et al., 2017). The starting point for this study is the Einstein-power-Maxwell theory with a vanishing cosmological constant in (3+1) dimensions, assuming a scale dependence of both the gravitational and the electromagnetic coupling. We further examine the corresponding thermodynamic properties and how these quantities experience deviations from their classical counterparts. We solve the effective Einstein’s field equations using the “null energy condition” to obtain analytical solutions. The implications of quantum corrections are also briefly discussed. Finally, we analyze our solutions and compare them to related results in the literature.

The increasing number of solution-processed laser compounds that can be implemented as low-cost, flexible, and/or integrated devices, makes necessary the development of reliable methods to delineate all their amplifying signatures and thus to open the door to appropriate cross-sample comparisons. Seeking to solve this problem, a new formalism to retrieve the losses and the optical gains from Amplified Spontaneous Emission (ASE) spectra as a function of the excitation density has been recently reported. In this manuscript, we explore the potential of this methodology to unveil relevant information on the photonic properties of the waveguiding devices and on the photophysics of the active materials. We demonstrate that the Variable Pump Intensity method opens the door to understand the relationship between the ASE thresholds and the optical gains and losses, it enables the extraction of the scattering/modal losses of the passive devices, and it can unveil the presence of leaky-modes and excited state absorption. In contrast, it does not perform too well in samples with multiple active species in its current implementation. We have substantiated all these findings using organic semiconductor thin films, several dye-doped polymer thin films and solutions of boron hydride.

The emergence of local moments in graphene zigzag edges, grain boundaries, vacancies and sp3 defects has been widely studied theoretically. However, conclusive experimental evidence is scarce. Recent progress in on-surface synthesis has made it possible to create nanographenes, such as triangulenes, with local moments in their ground states, and to probe them using scanning tunneling microscope (STM) spectroscopy. Here we review the application of the theory of sequential and cotunneling transport to relate the dI/dV spectra with the spin properties of nanographenes probed by STM. This approach permits us to connect the dI/dV with the many-body energies and wavefunctions of the graphene nanostructures. We apply this method describing the electronic states of the nanographenes by means of exact diagonalization of the Hubbard model within a restricted Active Space. This permits us to provide a proper quantum description of the emergence of local moments in graphene and its interplay with transport. We discuss the results of this theory in the case of diradical nanographenes, such as triangulene, rectangular ribbons and the Clar’s goblet, that have been recently studied experimentally by means of STM spectroscopy. This approach permits us to calculate both the dI/dV spectra, that yields excitation energies, as well as the atomically resolved conductivity maps, that provide information on the wavefunctions of the collective spin modes.

In this work we show that spherically symmetric regular black holes with topologies other than S3 de Sitter cores cannot be excluded from Borde’s theorem. In particular, we prove that spacetime connectivity leads to an S3 core by discarding other allowed topologies, such as the orientable and non orientable S2 bundles over S1, for achronal slices. Finally, some conjectures regarding physical quantification of topology change in these spacetimes are discussed.

High mass X-ray binaries are among the brightest X-ray sources in the Milky Way, as well as in nearby Galaxies. Thanks to their highly variable emissions and complex phenomenology, they have attracted the interest of the high energy astrophysical community since the dawn of X-ray Astronomy. In more recent years, they have challenged our comprehension of physical processes in many more energy bands, ranging from the infrared to very high energies. In this review, we provide a broad but concise summary of the physical processes dominating the emission from high mass X-ray binaries across virtually the whole electromagnetic spectrum. These comprise the interaction of stellar winds with the high gravitational and magnetic fields of compact objects, the behaviour of matter under extreme magnetic and gravity conditions, and the perturbation of the massive star evolutionary processes by presence in a binary system. We highlight the role of the INTEGRAL mission in the discovery of many of the most interesting objects in the high mass X-ray binary class and its contribution in reviving the interest for these sources over the past two decades. We show how the INTEGRAL discoveries have not only contributed to significantly increase the number of high mass X-ray binaries known, thus advancing our understanding of the population as a whole, but also have opened new windows of investigation that stimulated the multi-wavelength approach nowadays common in most astrophysical research fields. We conclude the review by providing an overview of future facilities being planned from the X-ray to the very high energy domain that will hopefully help us in finding an answer to the many questions left open after more than 18 years of INTEGRAL scientific observations.

In this work we explore the connections between Newman–Penrose scalars, including the Penrose–Rindler -curvature, with the equation of state of asymptotically Anti-de Sitter Reissner–Nordström black holes. After briefly reviewing the equation of state for these black holes from the point of view of both the Extended Phase Space and the Horizon Thermodynamics approaches, a geometric splitting is given for such an equation in terms of the non vanishing Newman–Penrose scalars which define the -curvature at the horizon. From this splitting, a possible thermodynamical interpretation is developed for such scalars in the context of the black hole thermodynamics approaches initially discussed. Afterwards, the square root of the Bel–Robinson tensor is employed to propose conditions at the horizons in terms of pressures or energy densities, which can be understood as alternative thermodynamical definitions of these surfaces.

An ionic Hamiltonian based on the first Hund rule applied to transition metal atoms is reviewed and discussed in detail. The tunneling current between a STM-tip and a transition metal atom is analyzed by means of that Hamiltonian combined with an effective crystal-field effect. We use an equation of motion (EOM) method to calculate that inelastic tunneling current, as well as the Kondo resonance appearing at the Fermi level. We show how an accurate description of its Kondo resonance for the Co/Cu2N(100) system can be achieved by extending the EOM-calculation up to fourth-order in the atom/metal interaction that defines the parameter of expansion in the EOM-equations. These results allow us to calculate also the inelastic tunneling excitation of the atom and the dynamical fluctuations of the atomic spin from S = 3/2 to S = 1.

The design and fabrication of thin-film based organic optoelectronic devices require knowledge of the film optical properties. A low-cost and non-destructive method often used for optical characterization of films is the well-established spectrophotometric envelope method. However, this method is typically limited to thickness above 400 nm, a value often higher than that of the films involved in these devices. This paper studies a procedure to obtain the thickness of sub-400 nm active films from their spectrophotometric trace when the refractive index is previously known. The proposed procedure is based on comparing the experimental transmission spectrum in the transparent spectral window with that obtained by simulation. The capabilities of the proposed method are demonstrated here by its application in the fabrication of organic distributed feedback lasers, for which a fine control of film thickness is important to obtain an optimized and reproducible response. Results are verified with other techniques, such as ellipsometry and profilometry. Thus, with the proposed method, film thickness can be easily determined down to 40 nm maintaining an accuracy of about 5 nm even for films with low refractive index (1.5–1.7). Different methods to determine refractive index of these films are also discussed.

Zigzag edges of neutral armchair–oriented Graphene Nano–Ribbons show states strongly localized at those edges. They behave as free radicals that can capture electrons during processing, increasing ribbon's stability. Thus, charging and its consequences should be investigated. Total energy calculations of finite ribbons using spin–polarized Density Functional Theory (DFT) show that ribbon's charging is feasible. Energies for Pariser-Parr-Pople (PPP) model Hamiltonian are compatible with DFT allowing the study of larger systems. Results for neutral ribbons indicate: i) the fundamental gap of spin–polarized (non–polarized) solutions is larger (smaller) than experimental data, ii) the ground state is spin–polarized, a characteristic still not observed experimentally. Total energy of GNRs decreases with the number of captured electrons reaching a minimum for a number that mainly depends on zigzag–edges size. The following changes with respect to neutral GNRs are noted: i) the ground state is not spin–polarized, ii) fundamental gap is in-between that of spin–polarized and non–polarized solutions of neutral ribbons, iii) while in neutral ribbons valence and conduction band onsets vs. the fundamental gap, linearly and symmetrically approach mid–gap with slope 0.5, charging induces Fermi level pinning, i.e., the slopes of the valence and conduction bands being about 0.1 and 0.9, in agreement with experiment.

We address the interplay between stacking and interlayer exchange for ferromagnetically ordered CrI3, both for bilayers and bulk. Whereas bulk CrI3 is ferromagnetic, both magneto-optical and transport experiments show that interlayer exchange for CrI3 bilayers is antiferromagnetic. Bulk CrI3 is known to assume two crystal structures, rhombohedral and monoclinic, that differ mostly in the stacking between monolayers. Below 210–220 K, bulk CrI3 orders in a rhombohedral phase. Our density functional theory calculations show a very strong dependence of interlayer exchange and stacking. Specifically, the ground states of both bulk and free-standing CrI3 bilayers are ferromagnetic for the rhombohedral phase. In contrast, the energy difference between both configurations is more than one order of magnitude smaller for the monoclinic phase, and eventually becomes antiferromagnetic when either positive strain or on-site Hubbard interactions (U ≥ 3) are considered. We also explore the interplay between interlayer hybridization and stacking, using a Wannier basis, and between interlayer hybridization and relative magnetic alignment for CrI3 bilayers, that helps to account for the very large tunnel magnetoresistance observed in recent experiments.

The object kinetic Monte Carlo (OKMC) method has proven to be an excellent tool to better understand microstructure evolution in irradiated materials, from metals to semiconductors. Its most valuable capability is that it provides a way to connect parameters obtained from fundamental models, such as first principles calculations, to experimental observations by expanding simulated time and length scales. However, the OKMC method has many limitations that pose questions on its predictive capabilities and an important effort is taking place to improve the model. In this review, first we describe the object kinetic Monte Carlo methodology, then a few examples are presented in the field of radiation damage of metals and the limitations of the method and its applicability discussed. To conclude, an outlook on the future of this computational model is given.

In the interior of neutron stars, the induction equation regulates the long-term evolution of the magnetic fields by means of resistivity, Hall dynamics and ambipolar diffusion. Despite the apparent simplicity and compactness of the equation, the dynamics it describes is not trivial and its understanding relies on accurate numerical simulations. While a few works in 2D have reached a mature stage and a consensus on the general dynamics at least for some simple initial data, only few attempts have been performed in 3D, due to the computational costs and the need for a proper numerical treatment of the intrinsic non-linearity of the equation. Here, we carefully analyze the general induction equation, studying its characteristic structure, and we present a new Cartesian 3D code, generated by the user-friendly, publicly available Simflowny platform. The code uses high-order numerical schemes for the time and spatial discretization, and relies on the highly-scalable SAMRAI architecture for the adaptive mesh refinement. We present the application of the code to several benchmark tests, showing the high order of convergence and accuracy achieved and the capabilities in terms of magnetic shock resolution and three-dimensionality. This paper paves the way for the applications to a realistic, 3D long-term evolution of neutron stars interior and, possibly, of other astrophysical sources.

The Kinetic Monte Carlo (KMC) algorithm is a particularly apt technique to simulate the complex processing of semiconductor devices. In this review, some of the main processes used for semiconductor industries to manufacture transistor from semiconductor materials, namely implantation, annealing and epitaxial growth are reviewed. The evolution of defects created during such processing for the particular, and well known case, of silicon, is commented. Kinetic Monte Carlo modeling is introduced and contrasted briefly with a continuum approach. Particular models of different phenomena, using both object and lattice KMC, are shown: point defect migration, cluster formation, dopant activation and deactivation, damage accumulation, amorphization, recrystallization, solid phase and selective epitaxial regrowth, etc. In this work we describe the models, its implementation into KMC, and we show several comparisons with significant experimental data validating the KMC approach and showing its capabilities. How extra capabilities can be included by extending the models to current problems in the semiconductor industry is also commented, in particular the use of SiGe alloys and the introduction of stress dependencies.

In the present work a new material based on the recently developed graphite flakes-SiC particles/metal composite, is described. The latter was processed by gas-pressure infiltration of the liquid metal into a preform obtained by packing a mixture of graphite flakes and SiC particles. Its microstructure consists of alternating layers of oriented graphite flakes and metal-particles composite, and, thus, it is highly anisotropic. Its highest thermal conductivity (>300 Wm−1K−1), attained in the plane parallel to the flakes plane, makes it suitable for heat sinking applications. Replacing SiC by particles of similar size and of ferromagnetic nature (Fe, Co and Ni), a material with moderate-to-high magnetic permeability and reasonably high thermal conductivity, has been produced. Mixtures of packed magnetic particles and graphite flakes were infiltrated with pure magnesium. In order to avoid chemical reaction, Co and Ni particles were carbon coated. Optimizing the combination of thermal conductivity and magnetic properties requires proper control of liquid metal infiltration variables, such as, temperature, pressure and contact time before metal solidification.

The nano-scale dispersion of ordered/disordered phases in semi-crystalline polymers can strongly influence their performance e.g. in terms of mechanical properties and/or electronic properties. However, to reveal the latter in scanning electron microscopy (SEM) often requires invasive sample preparation (etching of amorphous phase), because SEM usually exploits topographical contrast or yield differences between different materials. However, for pure carbon materials the secondary spectra were shown to differ substantially with increased order/disorder. The aims here is to gain an understanding of the shape of secondary electron spectrum (SES) of a widely used semi-crystalline polymer regioregular poly(3-hexylthiophene-2,5-diyl), commonly known as P3HT, and its links to the underlying secondary electron emission mechanisms so SES can be exploited for the mapping the nano-morphology. The comparison of simulated and experimental SES shows an excellent agreement, revealing a peak (at about 0.8 eV) followed by a broad shoulder (between 2 eV and 4.5 eV) with respective relative intensities reflecting order/disorder.

Irradiation with low energy Ar ions of graphene membranes gives rise to changes in the mechanical properties of this material. These changes have been associated to the production of defects, mostly isolated vacancies. However, the initial state of the graphene membrane can also affect its mechanical response. Using molecular dynamics simulations we have studied defect production in graphene membranes irradiated with 140 eV Ar ions up to a dose of 0.075 × 1014 ions/cm2 and different initial strains, from −0.25% (compressive strain) to 0.25% (tensile strain). For all strains, the number of defects increases linearly with dose with a defect production of about 80% (80 defects every 100 ions). Defects are mostly single vacancies and di-vacancies, although some higher order clusters are also observed. Two different types of di-vacancies have been identified, the most common one being two vacancies at first nearest neighbours distance. Differences in the total number of defects with the applied strain are observed which is related to the production of a higher number of di-vacancies under compressive strain compared to tensile strain. We attribute this effect to the larger out-of-plane deformations of compressed samples that could favor the production of defects in closer proximity to others.

We review the problem of spin decoherence of magnetic atoms deposited on a surface. Recent breakthroughs in scanning tunnelling microscopy (STM) make it possible to probe the spin dynamics of individual atoms, either isolated or integrated in nanoengineered spin structures. Transport pump and probe techniques with spin polarized tips permit measuring the spin relaxation time T1T1, while novel demonstration of electrically driven STM single spin resonance has provided a direct measurement of the spin coherence time T2T2 of an individual magnetic adatom. Here we address the problem of spin decoherence from the theoretical point of view. First we provide a short general overview of decoherence in open quantum systems and we discuss with some detail ambiguities that arise in the case of degenerate spectra, relevant for magnetic atoms. Second, we address the physical mechanisms that allows probing the spin coherence of magnetic atoms on surfaces. Third, we discuss the main spin decoherence mechanisms at work on a surface, most notably, Kondo interaction, but also spin–phonon coupling and dephasing by Johnson noise. Finally, we briefly discuss the implications in the broader context of quantum technologies.

Experiments showed that multiwalled carbon nanotubes (MWCNT) can be used as masks gainst irradiation to create metallic nanowires in a substrate. In order to understand the limitations of this application, it is interesting to know the energy and number of carbon atoms emerging from the MWCNT after the irradiation and how the structure of the MWCNT is modified. Using a molecular dynamics code that we have previously developed, we have simulated the continuous irradiation of MWCNT with carbon and argon projectiles. We have obtained that the use of carbon instead of argon to irradiate the MWCNT increases de effectiveness of the MWCNTs as masks, due to the ability of the carbon projectiles to be part of the MWCNT structure and partially mend the damage produced during irradiation. We have analyzed the number, energy, and spatial distribution of the recoils generated during irradiation and the change of the MWCNT structure as a function of the incident energy (100 and 500 eV), fluence (up to 4:5 · 1015 ions=cm2), and number of shells (up to 5-shells) of the MWCNT. These results determine the effectiveness of MWCNT as a mask, being useful to understand whether the atoms emerging from the MWCNT produce damage in the substrate or not. We find that for carbon projectiles the efficiency of MWCNT as masks does not depend much on the fluence, but on the number of nanotube shells and projectile incident energy. On the other hand, for a given nanotube and fluence, we observe a threshold incident energy below which the nanotube acts as a perfect mask.

The manuscript shows that nano-engineering the surface of diamond particles prior contacting the liquid metal strongly enhances the Thermal Conductivity (TC) of Al/diamond composites. Composites were fabricated by gas pressure infiltration within a two-step engineering procedure: i) diamond surface was in situ subjected to gas desorption by annealing at 760 °C or 850 °C, and, ii) the contact time between liquid metal and diamond was strictly controlled. The synergic action of surface modification and controlled processing conditions allows an outstanding increasing of TC from 422 W/mK to 734 W/mK (around 42% of increment) in composites fabricated with medium-quality diamond particles.

Solution-processed polymer films are used in multiple technological applications. The presence of residual solvent in the film, as a consequence of the preparation method, affects the material properties, so films are typically subjected to post-deposition thermal annealing treatments aiming at its elimination. Monitoring the amount of solvent eliminated as a function of the annealing parameters is important to design a proper treatment to ensure complete solvent elimination, crucial to obtain reproducible and stable material properties and therefore, device performance. Here we demonstrate, for the first time to our knowledge, the use of an organic distributed feedback (DFB) laser to monitor with high precision the amount of solvent extracted from a spin-coated polymer film as a function of the thermal annealing time. The polymer film of interest, polystyrene in the present work, is doped with a small amount of a laser dye as to constitute the active layer of the laser device and deposited over a reusable DFB resonator. It is shown that solvent elimination translates into shifts in the DFB laser wavelength, as a consequence of changes in film thickness and refractive index. The proposed method is expected to be applicable to other types of annealing treatments, polymer-solvent combinations or film deposition methods, thus constituting a valuable tool to accurately control the quality and reproducibility of solution-processed polymer thin films.

The idea of using carbon nanotubes (CNTs) as masks against irradiation has recently emerged, because of the region of a given material covered by a CNT can be protected from the effects of irradiation, creating nanowires. In this case, it is interesting to know in detail the number of generated recoils and their energy. In order to obtain these data, we simulate the irradiation of CNTs with carbon ions using a molecular dynamics code. To describe the interaction between carbon ions we use the Brenner potential joined smoothly to the Universal ZBL potential at short distances. We have analyzed the energy distributions of the carbon atoms emerging from the CNT for single projectile irradiation with incident energies from 30 eV to 5 keV. Our results show that the number and the energy of the recoil carbon atoms emerging from the CNT increases with the projectile incident energy. In average, each projectile with incident energy of 1 keV produces ∼3.6 recoils, which have a mean energy of 150 eV, while projectiles with 5 keV produce ∼7 recoils with a mean energy of 400 eV.

We present molecular dynamics simulations with empirical potentials to study the type of defects produced when irradiating graphene with low energy carbon ions (100 eV and 200 eV) and different dose rates. Simulations show the formation of very stable structures such as dimers, single chains of carbons and double chains of carbons. These structures are similar to those described in the literature, observed experimentally when irradiating graphene. For high doses or dose rates, the formation of nanopores is observed, similar to previous results by other authors for higher energies of the implanted ions. These simulations show how tunning the different parameters of irradiation conditions can be used to selectively create defects in graphene.

The edges of graphene and graphene like systems can host localized states with evanescent wave function with properties radically different from those of the Dirac electrons in bulk. This happens in a variety of situations, that are reviewed here. First, zigzag edges host a set of localized non-dispersive state at the Dirac energy. At half filling, it is expected that these states are prone to ferromagnetic instability, causing a very interesting type of edge ferromagnetism. Second, graphene under the influence of external perturbations can host a variety of topological insulating phases, including the conventional quantum Hall effect, the quantum anomalous Hall (QAH) and the quantum spin Hall phase, in all of which phases conduction can only take place through topologically protected edge states. Here we provide an unified vision of the properties of all these edge states, examined under the light of the same one orbital tight-binding model. We consider the combined action of interactions, spin–orbit coupling and magnetic field, which produces a wealth of different physical phenomena. We briefly address what has been actually observed experimentally.

We have calculated the lateral spread of the dose distribution of protons in liquid water by means of the SEICS (Simulation of Energetic Ions and Clusters through Solids) code, which properly accounts for the electronic stopping force (including energy-loss straggling), multiple elastic scattering with the target nuclei, dynamical electron charge-exchange processes and nuclear fragmentation reactions between the projectile and the nuclei of the target. Due to the multiple elastic scattering processes part of the proton energy may be deposited at a given lateral distance from the initial beam direction, which is quantified by the root mean square radius (rrms). We find in our simulations that the rrms follows a parabolic dependence as a function of the depth in the target and the quotient between the rrms at the Bragg peak and the depth of the Bragg peak is around 3% independently of the proton energy. A rather good agreement is obtained when comparing our results of rrms with experimental data and with other models.

Within the frame of heat dissipation for electronics, a very interesting family of anisotropic composite materials, fabricated by liquid infiltration of a matrix into preforms of oriented graphite flakes and SiC particles, has been recently proposed. Aiming to investigate the implications of the inherent anisotropy of these composites on their thermal conductivity, and hence on their potential applications, materials with matrices of Al–12 wt.% Si alloy and epoxy polymer have been fabricated. Samples have been cut at a variable angle with respect to the flakes plane and thermal conductivity has been measured by means of two standard techniques, namely, steady state technique and laser flash method. Experimental results are presented and discussed in terms of current models, from which important technological implications for heat sinking design can be derived.

The refractive index sensing capabilitity of distributed feedback (DFB) lasers based on highly photostable (under ambient conditions) perylenediimide-based active films, are reported. The sensor bulk sensitivity is determined from changes in the laser emission wavelength upon exposure to different liquids. The role of the active film thickness (hf) on the sensor sensitivity and on the laser parameters is studied. Sensors based on very thin films (hf = 160 nm) show the highest sensitivities, but their laser thresholds are relatively high and their operational durabilities moderate. The use of thicker films (hf = 850 nm) allows reducing the laser threshold and increasing the durability by two orders of magnitude. In this case, a higher sensitivity is achieved when the sensor operates at the wavelength corresponding to the first-order TE1 mode, instead of at the TE0 one. Finally, it is also shown that the inclusion of a high refractive index TiO2 layer on top of the sensor structure improves the sensitivity by around two times.

We simulate the irradiation of carbon nanotubes (CNT) with carbon ions using a molecular dynamics code. In order to describe the interaction between carbon ions we use the Tersoff or Brenner potential, both joined smoothly to the Universal ZBL potential at short distances. We have analyzed the defects produced after irradiation, the subsequent modification of the CNT structure, and their dependence on the used interatomic potential, the projectile energy (from 10 eV to 5 keV) and the dose. For single projectile irradiation, we have obtained that the coordination defect number increases with the projectile energy, although a saturation value is achieved at high projectile energies (∼3 keV). For continuous projectile irradiation, we have observed that for low energies (∼10 eV) the accumulation of adatoms produces a bump in the irradiated region. However, at intermediate energies (∼100 eV) the irradiation produces vacancies which are healed through non-hexagonal rings. This gives rise to a shrinking of the CNT diameter in the irradiated region. Finally, if the projectile energy is high enough (∼1 keV) the continuous irradiation produces the breaking of the CNT.

In the present work thermal-nanoimprint lithography of various commercial thermoplastic resists as matrixes for perylenediimides (PDIs) has been studied. This fabrication method reduces the number of fabrication steps, and therefore, the cost of the obtained distributed feedback (DFB) lasers. The optical properties of these devices are analyzed, aiming to optimize their performance.

The energy delivered by a swift proton beam in materials of interest to hadron therapy (liquid water, polymethylmethacrylate or polystyrene) is investigated. An explicit condensed-state description of the target excitation spectrum based on the dielectric formalism is used to calculate the energy-loss rate of the beam in the irradiated materials. This magnitude is the main input in the simulation code SEICS (Simulation of Energetic Ions and Clusters through Solids) used to evaluate the dose as a function of the penetration depth and radial distance from the beam axis.

We consider the collapse of a charged radiation fluid in a Planck-suppressed quadratic extension of General Relativity (GR) formulated à la Palatini. We obtain exact analytical solutions that extend the charged Vaidya-type solution of GR, which allows to explore in detail new physics at the Planck scale. Starting from Minkowski space, we find that the collapsing fluid generates wormholes supported by the electric field. We discuss the relevance of our findings in relation to the quantum foam structure of space–time and the meaning of curvature divergences in this theory.

The depth-dose distribution of proton beams in materials currently used in dosimetry measurements, such as liquid water, PMMA or graphite are calculated with the SEICS (Simulation of Energetic Ions and Clusters through Solids) code, where all the relevant effects in the evaluation of the energy deposited by the beam in the target are included, such as electronic energy-loss (including energy-loss straggling), multiple elastic scattering, electronic charge-exchange processes, and nuclear fragmentation interactions. Water equivalent properties are obtained for different proton beam energies and several targets of interest in dosimetry.

Al/diamond composites containing diamond particles of different qualities have been manufactured by gas pressure-assisted metal infiltration and characterized by thermal conductivity (TC) measurements. The results show that the intrinsic thermal conductivity of diamond (varied with the diamond quality) plays a minor role on TC. TC is mainly governed by the Al–diamond interface characteristics, which are determined by a proper control exerted through processing conditions. Albeit a very low cost and low quality diamond is used, a high value of 667 W/m K has been measured for Al/diamond composites produced under optimized processing conditions. Values above 740 W/m K are reported for the best diamond quality explored in this work. These experimental results, which assign the control over TC mainly to the interface conductance, suggest that many of the limiting values of TC reported in literature for the different explored metal–diamond systems, need to be reconsidered by proper precise control of interface evolution.

In this work, we introduce the Object Kinetic Monte Carlo (OKMC) simulator MMonCa and simulate the defect evolution in three different materials. We start by explaining the theory of OKMC and showing some details of how such theory is implemented by creating generic structures and algorithms in the objects that we want to simulate. Then we successfully reproduce simulated results for defect evolution in iron, silicon and tungsten using our simulator and compare with available experimental data and similar simulations. The comparisons validate MMonCa showing that it is powerful and flexible enough to be customized and used to study the damage evolution of defects in a wide range of solid materials.

The effects of processing conditions on the thermal conductivity (TC) of aluminum/diamond composites fabricated by means of gas-pressure infiltration, have been evaluated using a device that allows a highly precise control of infiltration temperature and contact time between the liquid metal and diamond. Both variables have strong effects on the TC of final materials, through chemical and morphological modifications of the interface. Thus, maximizing heat conduction requires a proper choice of those two variables. TC’s up to 670 W/mK have been obtained.