rossella zaffino | IMB-CNM / CSIC (original) (raw)

Papers by rossella zaffino

ACS Applied Electronic Materials

Composites exhibit unique synergistic properties emerging when components with different properti... more Composites exhibit unique synergistic properties emerging when components with different properties are combined. The tuning of the energy bandgap in the electronic structure of the material allows designing tailor-made systems with desirable mechanical, electrical, optical, and/or thermal properties. Here, we study an emergent insulator−metal transition at room temperature in bilayered (BL) thin-films comprised of polycarbonate/ molecular-metal composites. Temperature-dependent resistance measurements allow monitoring of the electrical bandgap, which is in agreement with the optical bandgap extracted by optical absorption spectroscopy. The semiconductor-like properties of BL films, made with bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF or ET) α-ET 2 I 3 (nano)microcrystals as two-dimensional molecular conductor on one side and insulator polycarbonate as a second ingredient, are attributed to an emergent phenomenon equivalent to the transition from an insulator to a metal. This made it possible to obtain semiconducting BL films with tunable electrical/optical bandgaps ranging from 0 to 2.9 eV. A remarkable aspect is the similarity close to room temperature of the thermal and mechanical properties of both composite components, making these materials ideal candidates to fabricate flexible and soft sensors for stress, pressure, and temperature aiming at applications in wearable human health care and bioelectronics.

Plasma Physics and Controlled Fusion, 2020

Laser-plasma interactions at high intensities are often accompanied by emission of a strong elect... more Laser-plasma interactions at high intensities are often accompanied by emission of a strong electromagnetic pulse (EMP) interfering with particle detectors or other electronic equipment. We present experimental evidence for significant differences in noise amplitudes in laser-proton acceleration from aluminium as compared to mylar target foils. Such dissimilarities have been consistently observed throughout two series of measurements indicating that, under otherwise identical conditions, the target conductivity is the principal parameter related to EMP generation. In addition, the lateral size of the target foils correlates with the absolute noise levels. A frequency analysis combined with numerical simulations allows for an identification of several sources of radiofrequency emission in the MHz-GHz regime. Further, the temporal evolution of single frequencies on the nanosecond scale provides information on distinct excitation mechanisms.

Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology, 2015

Biosensors, small devices enabling selective bioanalysis because of properly assembled biological... more Biosensors, small devices enabling selective bioanalysis because of properly assembled biological recognition molecules, represent the fortuitous results of years of interdisciplinary and complementary investigations in different fields of science. The ultimate role of a biosensor is to provide coupling between the recognition element and the analyte of interest, bringing a quantitative value of its concentrations into a complex sample matrix. They offer many advantages. Among them, portability, low cost with fast response times, and the possibility to operate in situ without the need for sample preparation are certainly the most important. Among biosensors, a large space is occupied by DNA biosensors. Screening genomic DNA is of fundamental importance for the development of new tools available to physicians during the clinical process. Sequencing of individual human genomes, accomplished principally by microarrays with optical detection, is complex and expensive for current clinical protocols. Efforts in research are focused on simplifying and reducing the cost of DNA biosensors. For this purpose, other transduction techniques are under study to make more portable and affordable DNA biosensors. Compared with traditional optical detection tools, electrochemical methods allow the same sensitivity and specificity but are less expensive and less labor intensive. Scalability of electrochemical devices makes it possible to use the advantages introduced by nanosized components. The involvement of nanomaterials and nanostructures with custom-tailored shapes and properties is expected to rapidly boost the field of electrochemical DNA biosensors and, in general, that of next-generation sequencing technologies.

Physical Review A, 2007

We discuss the ground state entanglement of the E ⊗ ǫ Jahn-Teller model in the presence of a stro... more We discuss the ground state entanglement of the E ⊗ ǫ Jahn-Teller model in the presence of a strong transverse magnetic field as a function of the vibronic coupling strength. A complete characterization is given of the phenomenon of entanglement sharing in a system composed by a qubit coupled to two bosonic modes. Using the residual I-tangle, we find that three-partite entanglement is significantly present in the system in the parameter region near the bifurcation point of the corresponding classical model.

Physical Review A, 2006

We discuss the ground state entanglement of a bi-partite system, composed by a qubit strongly int... more We discuss the ground state entanglement of a bi-partite system, composed by a qubit strongly interacting with an oscillator mode, as a function of the coupling strenght, the transition frequency and the level asymmetry of the qubit. This is done in the adiabatic regime in which the time evolution of the qubit is much faster than the oscillator one. Within the adiabatic approximation, we obtain a complete characterization of the ground state properties of the system and of its entanglement content.

Nanotechnology, 2014

We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transpor... more We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transport for the label-free and direct electrical detection of DNA hybridization. This biosensor platform comprises an array of vertical nano-gap biosensors made of gold and fabricated through standard photolithography combined with focused ion beam lithography. The nano-gap walls are covalently modified with short, anti-symmetric thiolated DNA probes, which are terminated by 19 bases complementary to both the ends of a target DNA strand. The nano-gaps are separated by a distance of 50nm, which was adjusted to fit the length of the DNA target plus the DNA probes. The hybridization of the target DNA closes the gap circuit in a switch on/off fashion, in such a way that it is readily detected by an increase in the current after nano-gap closure. The nano-biosensor shows high specificity in the discrimination of base-pair mismatching and does not require signal indicators or enhancing molecules. The design of the biosensor platform is applicable for multiplexed detection in a straightforward manner. The platform is well-suited to mass production, point-of-care diagnostics, and wide-scale DNA analysis applications.

We discuss the ground state entanglement of the E??? ?? Jahn-Teller model in the presence of a st... more We discuss the ground state entanglement of the E??? ?? Jahn-Teller model in the presence of a strong transverse magnetic field as a function of the vibronic coupling strength. A complete characterization is given of the phenomenon of entanglement sharing in a system ...

Physical Review Letters, 2008

We study the exact entanglement dynamics of two atoms in a lossy resonator. Besides discussing th... more We study the exact entanglement dynamics of two atoms in a lossy resonator. Besides discussing the steady-state entanglement, we show that in the strong coupling regime the system-reservoir correlations induce entanglement revivals and oscillations and propose a strategy to fight against the deterioration of the entanglement using the quantum Zeno effect.

The thermodynamic properties of N two-level atoms coupled to radiation field are analyzed taking ... more The thermodynamic properties of N two-level atoms coupled to radiation field are analyzed taking into account the diamagnetic term by a slight modification to the usual approach to quantizing the electromagnetic field. Following this procedure, we are able to solve the discrepancy originating in the use of different states as a basis for expressing the state of radiation field. We develop a perturbative expansion of partition function and a simple analytic expression is found for a high coupling constant. We show that, in this limit, the interaction of independent atomic spins with a single photon mode can be interpreted as an effective spin-spin interaction of long range nature. Even in this approach, if the diamagnetic term is taken into account, a phase transition at nonzero temperature cannot occur due to sum-rule arguments.

PACS numbers: 42.50.Fx -Cooperative phenomena in quantum optical systems; 05.70.Jk -Critical poin... more PACS numbers: 42.50.Fx -Cooperative phenomena in quantum optical systems; 05.70.Jk -Critical point phenomena; 73.43.Nq -Quantum phase transition. In their Comment [1], Brankov, Tonchev and Zagrebnov, claim that the temperature-dependent effective Hamiltonian derived in Ref. [2] from a radiation-matter Dicke model violate a "rigorous" result that the same authors have obtained 30 years ago [3]. It is clear that Brankov, Tonchev and Zagrebnov have misunderstood the results of Ref. [2] in several ways. 1. First, the temperature-dependent effective Hamiltonian given by

International Journal of Modern Physics E, 2005

The unusual structure of 11 Li, the first halo nucleus found, is analyzed by the Preparata model ... more The unusual structure of 11 Li, the first halo nucleus found, is analyzed by the Preparata model of nuclear structure. By applying Coherent Nucleus Theory, we obtain an interaction potential for the halo-neutrons that rightly reproduces the fundamental state of the system.

Physical Review B, 2008

We analyze the Kitaev model on the triangle-honeycomb lattice whose ground state has recently bee... more We analyze the Kitaev model on the triangle-honeycomb lattice whose ground state has recently been shown to be a chiral spin liquid. We consider two perturbative expansions : the isolateddimer limit containing Abelian anyons and the isolated-triangle limit. In the former case, we derive the low-energy effective theory and discuss the role played by multi-plaquette interactions. In this phase, we also compute the spin-spin correlation functions for any vortex configuration. In the isolated-triangle limit, we show that the effective theory is, at lowest nontrivial order, the Kitaev honeycomb model at the isotropic point. We also compute the next-order correction which opens a gap and yields non-Abelian anyons.

Physical Review A, 2007

Physical Review A, 2006

Nanotechnology, 2014

We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transpor... more We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transport for the label-free and direct electrical detection of DNA hybridization. This biosensor platform comprises an array of vertical nano-gap biosensors made of gold and fabricated through standard photolithography combined with focused ion beam lithography. The nano-gap walls are covalently modified with short, anti-symmetric thiolated DNA probes, which are terminated by 19 bases complementary to both the ends of a target DNA strand. The nano-gaps are separated by a distance of 50 nm, which was adjusted to fit the length of the DNA target plus the DNA probes. The hybridization of the target DNA closes the gap circuit in a switch on/off fashion, in such a way that it is readily detected by an increase in the current after nano-gap closure. The nano-biosensor shows high specificity in the discrimination of base-pair mismatching and does not require signal indicators or enhancing molecules. The design of the biosensor platform is applicable for multiplexed detection in a straightforward manner. The platform is well-suited to mass production, point-of-care diagnostics, and wide-scale DNA analysis applications.

The European Physical Journal B, 2005

We discuss the problem of a N two-level systems interacting with a single radiation mode in the s... more We discuss the problem of a N two-level systems interacting with a single radiation mode in the strong-coupling regime. The thermodynamic properties of Dicke model are analyzed developing a perturbative expansion of the partition function in the high-temperature limit and we use this method to investigate the connections between the Dicke and the collective one-dimensional Ising model.

Physical Review Letters, 2008

ACS Applied Electronic Materials

Plasma Physics and Controlled Fusion, 2020

Wiley Interdisciplinary Reviews: Nanomedicine and Nanobiotechnology, 2015

Physical Review A, 2007

Physical Review A, 2006

Nanotechnology, 2014

Physical Review Letters, 2008

International Journal of Modern Physics E, 2005

Physical Review B, 2008

Physical Review A, 2007

Physical Review A, 2006

Nanotechnology, 2014

We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transpor... more We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transport for the label-free and direct electrical detection of DNA hybridization. This biosensor platform comprises an array of vertical nano-gap biosensors made of gold and fabricated through standard photolithography combined with focused ion beam lithography. The nano-gap walls are covalently modified with short, anti-symmetric thiolated DNA probes, which are terminated by 19 bases complementary to both the ends of a target DNA strand. The nano-gaps are separated by a distance of 50 nm, which was adjusted to fit the length of the DNA target plus the DNA probes. The hybridization of the target DNA closes the gap circuit in a switch on/off fashion, in such a way that it is readily detected by an increase in the current after nano-gap closure. The nano-biosensor shows high specificity in the discrimination of base-pair mismatching and does not require signal indicators or enhancing molecules. The design of the biosensor platform is applicable for multiplexed detection in a straightforward manner. The platform is well-suited to mass production, point-of-care diagnostics, and wide-scale DNA analysis applications.

The European Physical Journal B, 2005

Physical Review Letters, 2008