Unraveling the Spin-to-Charge Current Conversion Mechanism and Charge Transfer Dynamics at the Interface of Graphene/WS Heterostructures at Room Temperature.

We report experimental investigations of spin-to-charge current conversion and charge transfer (CT) dynamics at the interface of the graphene/WS van der Waals heterostructure. Pure spin current was produced by the spin precession in the microwave-driven ferromagnetic resonance of a permalloy film (Py=NiFe) and injected into the graphene/WS heterostructure through a spin pumping process. The observed spin-to-charge current conversion in the heterostructure is attributed to the inverse Rashba-Edelstein effect (IREE) at the graphene/WS interface.

Stability and Optoelectronic Properties of Two-Dimensional Gallium Phosphide.

Using first-principles calculations, density functional theory, and the tight-binding method, we investigate the optoelectronic properties of two-dimensional gallium phosphide (2D GaP). Our investigation covers electronic properties, such as band structure and electronic band gap, and optical properties, including absorption spectra, refractive index, and reflectivity, considering excitonic effects. Additionally, structural aspects such as stability, elastic properties, and Raman and infrared spectra are also analyzed.

Exploring charge density distribution and electronic properties of hybrid organic-germanium layers.

Band gap tuning and dielectric properties of small organic ligands adsorbed on bidimensional germanium monolayers (germanene) have been investigated using first-principles calculations. We show that the adsorption of these small groups retains the initially stable free-standing pristine buckled structure form. Charge density and chemical bonding analyses show that the ligands are chemisorbed on the germanium layers.

Structural and topological phase transitions induced by strain in two-dimensional bismuth.

We employ first-principles density-functional calculations to study structural and topological electronic transitions in two-dimensional bismuth layers. Our calculations reveal that a free-standing hexagonal bismuthene phase (the most stable one in the absence of strain) should become thermodinamically unstable against transformation to a putative 'pentaoctite' phase (composed entirely of pentagonal and octagonal rings), under biaxial tensile strain. Moreover, our results indicate that 2D bismuth layers in the pentaoctite phase should undergo a topological electronic phase transition under either a biaxial or uniaxial tensile strain.

Bilayers of NiCS and PtCS: graphene-like 2D topological insulators tunable by electric fields.

In the present work we predict, through first-principles calculations, that bilayers of the recently synthesized Ni [Formula: see text] [Formula: see text] and Pt [Formula: see text] [Formula: see text] layered materials are topological insulators upon electron doping, and that their topological insulator properties can be modulated by the application of electric fields with magnitudes achievable in devices. The electronic structures of both bilayers are characterized by spin-orbit split graphene-like bands, with gap magnitudes that are three orders of magnitude larger than graphene's. In ribbon geometries, chiral edge modes develop at each side with band dispersions similar to that of Kane-Mele graphene model.

Topologically Protected Metallic States Induced by a One-Dimensional Extended Defect in the Bulk of a 2D Topological Insulator.

We report ab initio calculations showing that a one-dimensional extended defect generates topologically protected metallic states immersed in the bulk of two-dimensional topological insulators. We find that a narrow extended defect, composed of periodic units consisting of one octagonal and two pentagonal rings (a 558 extended defect), embedded in the hexagonal bulk of a bismuth bilayer, introduces two pairs of one-dimensional counterpropagating helical-Fermion electronic bands with the opposite spin-momentum locking characteristic of the topological metallic states that appear at the edges in two-dimensional topological insulators. Each one of these pairs of helical-Fermion bands is localized, respectively, along each one of the zigzag chains of bismuth atoms at the core of the 558 extended defect, and their hybridization leads to the opening of very small gaps (6 meV or less) in the helical-Fermion dispersions of these defect-related modes.

Postoperative mediastinitis in cardiovascular surgery postoperation. Analysis of 1038 consecutive surgeries.

Objective: To report the incidence of mediastinitis in cardiovascular surgery postoperation.

Methods: The records of all 1038 patients who underwent cardiovascular surgical procedures between May/2007 and June/2009 were reviewed. All operations were performed in Division of Cardiovascular Surgery of Pronto Socorro Cardiológico de Pernambuco - PROCAPE.