6,197 research outputs found
Kondo effect and spin quenching in high-spin molecules on metal substrates
Using a state-of-the art combination of density functional theory and
impurity solver techniques we present a complete and parameter-free picture of
the Kondo effect in the high-spin () coordination complex known as
Manganese Phthalocyanine adsorbed on the Pb(111) surface. We calculate the
correlated electronic structure and corresponding tunnel spectrum and find an
asymmetric Kondo resonance, as recently observed in experiments. Contrary to
previous claims, the Kondo resonance stems from only one of three possible
Kondo channels with origin in the Mn 3d-orbitals, its peculiar asymmetric shape
arising from the modulation of the hybridization due to strong coupling to the
organic ligand. The spectral signature of the second Kondo channel is strongly
suppressed as the screening occurs via the formation of a many-body singlet
with the organic part of the molecule. Finally, a spin-1/2 in the 3d-shell
remains completely unscreened due to the lack of hybridization of the
corresponding orbital with the substrate, hence leading to a spin-3/2
underscreened Kondo effect.Comment: 5 pages, 2 figure
Van der Waals spin valves
We propose spin valves where a 2D non-magnetic conductor is intercalated
between two ferromagnetic insulating layers. In this setup, the relative
orientation of the magnetizations of the insulating layers can have a strong
impact on the in-plane conductivity of the 2D conductor. We first show this for
a graphene bilayer, described with a tight-binding model, placed between two
ferromagnetic insulators. In the anti-parallel configuration, a band gap opens
at the Dirac point, whereas in the parallel configuration, the graphene bilayer
remains conducting. We then compute the electronic structure of graphene
bilayer placed between two monolayers of the ferromagnetic insulator CrI,
using density functional theory. Consistent with the model, we find that a gap
opens at the Dirac point only in the antiparallel configuration.Comment: 5 pages, 4 figure
Hydrogenated Graphene Nanoribbons for Spintronics
We show how hydrogenation of graphene nanoribbons at small concentrations can
open new venues towards carbon-based spintronics applications regardless of any
especific edge termination or passivation of the nanoribbons. Density
functional theory calculations show that an adsorbed H atom induces a spin
density on the surrounding orbitals whose symmetry and degree of
localization depends on the distance to the edges of the nanoribbon. As
expected for graphene-based systems, these induced magnetic moments interact
ferromagnetically or antiferromagnetically depending on the relative adsorption
graphene sublattice, but the magnitude of the interactions are found to
strongly vary with the position of the H atoms relative to the edges. We also
calculate, with the help of the Hubbard model, the transport properties of
hydrogenated armchair semiconducting graphene nanoribbons in the diluted regime
and show how the exchange coupling between H atoms can be exploited in the
design of novel magnetoresistive devices
Just-in-Time Education for Intensive Care Nurses
Background: Continuing education is fundamentally necessary to ensure ongoing competency of nurses in the Intensive Care Unit (ICU). There are many effective methods of continuing education, but there is a gap in continuing education for ICU nurses for high-risk low-frequency therapies (HRLFT).
Objectives: The purpose of this project was to determine if the implementation of Just-in-Time Education (JITE) for HRLFT in the Pediatric Intensive Care Unit (PICU) improved nurses’ feelings of competence, comfort, and safety when utilizing these interventions.
Methods: JITE checklists for nurses were developed for HRLFT in the PICU. The checklists were reviewed by the staff nurse and charge nurse when a nurse was assigned to a patient with a HRLFT. All nurses in the PICU received an email explaining the project and a pre-survey regarding their feelings of competence and comfort in regards to HRLFT before implementation of JITE checklists. Three months later the nurses received a post-survey addressing the same questions and questions regarding the effectiveness of JITE.
Results: Compared with baseline results, the post intervention survey showed nurses felt more comfortable and competent caring for patients receiving HRLFT. Nurses reported being more comfortable asking for education reinforcement and valued the one-on-one review time with the charge nurse. Eighty five percent of the nurses felt JITE should be continued and 15 percent were neutral.
Conclusions: The results of this study show that utilization of JITE provides a cost and time efficient method to ensure minimal competence for HRLFT in the ICU
Localized basis sets for unbound electrons in nanoelectronics
It is shown how unbound electron wave functions can be expanded in a suitably
chosen localized basis sets for any desired range of energies. In particular,
we focus on the use of gaussian basis sets, commonly used in first-principles
codes. The possible usefulness of these basis sets in a first-principles
description of field emission or scanning tunneling microscopy at large bias is
illustrated by studying a simpler related phenomenon: The lifetime of an
electron in a H atom subjected to a strong electric field.Comment: 6 pages, 5 figures, accepted by J. Chem. Phys. (http://jcp.aip.org/
MAXIMS: a computer program for estimating the food consumption of fishes from diel stomach contents data and population parameters
MAXIMS (Computer file), Food consumption, Stomach content, Population characteristics, Computer programmes Pisces
Alternatives for the development of new industrial crops for Patagonia
The search for potential arid-adapted crops has yielded several species that produce industrial raw materials and can be cultivated in warm arid lands. However, there are few species adapted to cold arid environments like Patagonia. The objectives of this paper are to propose criteria for the search and development of new industrial crops for Patagonia, to analyze those species that have been suggested as potential crops, and to propose other candidates based on these criteria. We discuss the potential of the few species cited as potential crops for Patagonia: Colliguaya integerrima (Euphorbiaceae) and Lesquerella mendocina (Brassicaceae) as seed-oil sources; Grindelia chiloensis (Asteraceae), Colliguaya integerrima, Larrea sp. (Zygophyllaceae), and Mulinum spinosum (Umbelliferae) as politerpene sources, and Prosopis and Cercicium sp. as gum sources. We include a description of prospective families for oils, gums and terpenes
Magnetic polaron and antiferro-ferromagnetic transition in doped bilayer CrI
Gate-induced magnetic switching in bilayer CrI has opened new ways for
the design of novel low-power magnetic memories based on van der Waals
heterostructures. The proposed switching mechanism seems to be fully dominated
by electrostatic doping. Here we explain, by first-principle calculations, the
ferromagnetic transition in doped bilayer CrI. For the case of a very small
electron doping, our calculations predict the formation of magnetic polarons
("ferrons", "fluctuons") where the electron is self-locked in a ferromagnetic
droplet in an antiferromagnetic insulating matrix. The self-trapping of holes
is impossible, at least, within our approximation.Comment: 5 pages, 5 figure
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