DFT+U and quantum Monte Carlo study of electronic and optical properties of AgNiO2 and AgNi1-xCoxO2 delafossite.

As the only semimetallic d10-based delafossite, AgNiO2 has received a great deal of attention due to both its unique semimetallicity and its antiferromagnetism in the NiO2 layer that is coupled with a lattice distortion. In contrast, other delafossites such as AgCoO2 are insulating. Here we study how the electronic structure of AgNi1-xCoxO2 alloys vary with Ni/Co concentration, in order to investigate the electronic properties and phase stability of the intermetallics. While the electronic and magnetic structure of delafossites have been studied using density functional theory (DFT), earlier studies have not included corrections for strong on-site Coulomb interactions. In order to treat these interactions accurately, in this study we use Quantum Monte Carlo (QMC) simulations to obtain accurate estimates for the electronic and magnetic properties of AgNiO2. By comparison to DFT results we show that these electron correlations are critical to account for. We show that Co doping on the magnetic Ni sites results in a metal-insulator transition near x ∼0.33, and reentrant behavior near x ∼ 0.66.

Nanoscale Control of the Metal-Insulator Transition at LaAlO3/KTaO3 Interfaces.

Recent reports of superconductivity at KTaO3 (KTO) (110) and (111) interfaces have sparked intense interest due to the relatively high critical temperature as well as other properties that distinguish this system from the more extensively studied SrTiO3 (STO)-based heterostructures. Here, we report the reconfigurable creation of conducting structures at intrinsically insulating LaAlO3/KTO(110) and (111) interfaces. Devices are created using two distinct methods previously developed for STO-based heterostructures: (1) conductive atomic-force microscopy lithography and (2) ultralow-voltage electron-beam lithography. At low temperatures, KTO(110)-based devices show superconductivity that is tunable by an applied back gate. A one-dimensional nanowire device shows single-electron-transistor (SET) behavior. A KTO(111)-based device is metallic but does not become superconducting. These reconfigurable methods of creating nanoscale devices in KTO-based heterostructures offer new avenues for investigating mechanisms of superconductivity as well as development of quantum devices that incorporate strong spin-orbit interactions, superconducting behavior, and nanoscale dimensions.

Strongly Correlated Aromatic Molecular Conductor.

Strongly correlated electronic molecules open the way for strong coupling between charge, spin, and lattice degrees of freedom to enable interdisciplinary fields, such as molecular electronic switches and plasmonics, spintronics, information storage, and superconducting circuits. However, despite exciting computational predictions and promising advantages to prepare flexible geometries, the electron correlation effect in molecules has been elusive. Here, the electron correlation effects of molecular plasmonic films are reported to uncover their coupling of charge, spin, lattice, and orbital for the switchable metal-to-insulator transition under external stimuli, at which the simultaneous transition occurs from the paramagnetic, electrical, and thermal conducting state to the diamagnetic, electrical, and thermal insulating state. In addition, density functional theory calculation and spectroscopic studies are combined to provide the mechanistic understanding of electronic transitions and molecular plasmon resonance observed in molecular conducting films. The self-assembled molecular correlated conductor paves the way for the next generation integrated micro/nanosystems.

Transformational Leadership Practices and Work Engagement Among Nurse Leaders.

OBJECTIVE: The aim of this study was to develop better understanding of the leadership characteristics of clinical nurse leaders. BACKGROUND: Transformational leaders are the essential to support nursing in taking control of patient and family care coordination. One prior study of leadership and work engagement among clinical nurse leaders was identified. METHODS: This descriptive correlational study explored the relationship between transformational leadership practices and work engagement among nurse leaders in the United States. Sample consisted of clinical nursing leaders attending the 2016 Magnet® Conference. RESULTS: A significant positive relationship was identified between leadership practices and work engagement. Differences were noted in areas of select leadership practices and work engagement among nurse leaders based on different levels of education. Nurse leaders underperform in inspiring a shared vision, support for innovation, and taking risks, while also showing relatively weak levels of engagement in areas of vigor and absorption. CONCLUSION: There is a need for additional research to better understand the characteristics of clinical nurse leaders to promote the principles of transformational leadership.

Impact of a Planned Workflow Change: Super Track Improves Quality and Service for Low-Acuity Patients at an Inner-City Hospital.

ED volume and acuity were anticipated to increase at an inner-city hospital. A strategy to mitigate the impact was needed. METHODS: A multidisciplinary team facilitated a workflow modification project implementing a Super Track to treat low-acuity patients. A literature review led to the creation of an evidence-based framework. Staff education regarding the change process and the results of an analysis in the strengths, weaknesses, opportunities, and threat format, along with simulation exercises and a pilot project, supported implementation of this strategy. RESULTS: Simulation exercises demonstrated that the proposed workflow with a Super Track had the potential to reduce the length of stay among level 4 and 5 patients coming to the emergency department. Implementing a Super Track reduced the patient arrival-to-provider time for low-acuity patients, but length of stay was not affected. After implementation, the number of patients who left without being seen decreased by 40%, and patient satisfaction increased by 36%. IMPLICATIONS FOR PRACTICE: A modified front-end workflow process produced a statistically significant, sustainable improvement in patient flow of low-acuity patients in our emergency department. Use of an evidence-based, multidisciplinary team approach supported the change process.

Antiferromagnetic Spin Seebeck Effect.

We report on the observation of the spin Seebeck effect in antiferromagnetic MnF_{2}. A device scale on-chip heater is deposited on a bilayer of MnF_{2} (110) (30 nm)/Pt (4 nm) grown by molecular beam epitaxy on a MgF_{2} (110) substrate. Using Pt as a spin detector layer, it is possible to measure the thermally generated spin current from MnF_{2} through the inverse spin Hall effect. The low temperature (2-80 K) and high magnetic field (up to 140 kOe) regime is explored. A clear spin-flop transition corresponding to the sudden rotation of antiferromagnetic spins out of the easy axis is observed in the spin Seebeck signal when large magnetic fields (>9 T) are applied parallel to the easy axis of the MnF_{2} thin film. When the magnetic field is applied perpendicular to the easy axis, the spin-flop transition is absent, as expected.

Paramagnetic spin seebeck effect.

We report the observation of the longitudinal spin Seebeck effect in paramagnetic insulators. By using a microscale on-chip local heater, we generate a large thermal gradient confined to the chip surface without a large increase in the total sample temperature. Using this technique at low temperatures (<20 K), we resolve the paramagnetic spin Seebeck effect in the insulating paramagnets Gd3Ga5O12 (gadolinium gallium garnet) and DyScO3 (DSO), using either W or Pt as the spin detector layer. By taking advantage of the strong magnetocrystalline anisotropy of DSO, we eliminate contributions from the Nernst effect in W or Pt, which produces a phenomenologically similar signal.

Oxygen-vacancy-induced polar behavior in (LaFeO3)2/(SrFeO3) superlattices.

Complex oxides displaying ferroelectric and/or multiferroic behavior are of high fundamental and applied interest. In this work, we show that it is possible to achieve polar order in a superlattice made up of two nonpolar oxides by means of oxygen vacancy ordering. Using scanning transmission electron microscopy imaging, we show the polar displacement of magnetic Fe ions in a superlattice of (LaFeO3)2/(SrFeO3) grown on a SrTiO3 substrate. Using density functional theory calculations, we systematically study the effect of epitaxial strain, octahedral rotations, and surface terminations in the superlattice and find them to have a negligible effect on the antipolar displacements of the Fe ions lying in between SrO and LaO layers of the superlattice (i.e., within La0.5Sr0.5FeO3 unit cells). The introduction of oxygen vacancies, on the other hand, triggers a polar displacement of the Fe ions. We confirm this important result using electron energy loss spectroscopy, which shows partial oxygen vacancy ordering in the region where polar displacements are observed and an absence of vacancy ordering outside of that area.

Redox Gating for Colossal Carrier Modulation and Unique Phase Control.

Redox gating, a novel approach distinct from conventional electrolyte gating, combines reversible redox functionalities with common ionic electrolyte moieties to engineer charge transport, enabling power-efficient electronic phase control. This study achieves a colossal sheet carrier density modulation beyond 1016 cm-2, sustainable over thousands of cycles, all within the sub-volt regime for functional oxide thin films. The key advantage of this method lies in the controlled injection of a large quantity of carriers from the electrolyte into the channel material without the deleterious effects associated with traditional electrolyte gating processes such as the production of ionic defects or intercalated species. The redox gating approach offers a simple and practical means of decoupling electrical and structural phase transitions, enabling the isostructural metal-insulator transition and improved device endurance. The versatility of redox gating extends across multiple materials, irrespective of their crystallinity, crystallographic orientation, or carrier type (n- or p-type). This inclusivity encompasses functional heterostructures and low-dimensional quantum materials composed of sustainable elements, highlighting the broad applicability and potential of the technique in electronic devices.

Women's decision-making regarding medication use in pregnancy for anxiety and/or depression.

AIM: To increase understanding of women's decision-making process concerning the medication use for anxiety and/or depression while pregnant. BACKGROUND: Anxiety and depression affects many pregnant women, yet the decision to take psychotropic medication is complex and possibly subject to social oppression. DESIGN: Cross-sectional descriptive survey design. METHODS: A web-based survey was used to collect data from a convenience sample of 143 pregnant women over 3 months beginning in early 2011. An independent t-test was conducted to determine differences in satisfaction between women with high and low levels of emancipated decision-making (EDM). A multiple regression analysis was conducted to determine which subscales of the emancipation scale best predict level of satisfaction with the decision. FINDINGS: The majority of respondents were White, between 25-34 years of age. The group with lower levels of emancipation reported lower mean satisfaction scores compared with those with higher levels of emancipation. Regression analysis showed that the three subscale emancipation model was a statistically significant predictor of satisfaction with the decision and accounted for 54% of the variance in satisfaction. The subconcept of personal knowledge was most predictive of satisfaction with decision. CONCLUSIONS: Women may be able to overcome oppressive forces by using an EDM process. EDM allows them to make a decision that feels right for them and to feel satisfied with the decision.

Career advancement and professional development in nursing.

BACKGROUND: Excellence underscores the need for nurses to keep their skills and competencies current through participation in professional development and career advancement. Evidence suggests that internationally educated nurses (IENs) progress relatively slowly through the career ladder and participate less in professional development compared with nurses educated in the United States (UENs). Mentorship and self-efficacy are considered major determinants of career advancement. PURPOSE: The aim of the study was to understand the differences in levels of mentorship function and self-efficacy as well as the differences in participation in professional development and career advancement between UENs and IENs. METHOD: A descriptive survey design was implemented using a Web-based survey. RESULTS: Significant disparities were noted in the role model function of mentoring and some professional development and career advancement measures between UENs and IENs. Mentorship is essential for professional growth. Sociodemographic characteristics of mentors are important because mentors are role models. CONCLUSION: Standardized career advancement structures are needed to promote professional growth.

Tunable superconductivity and its origin at KTaO3 interfaces.

What causes Cooper pairs to form in unconventional superconductors is often elusive because experimental signatures that connect to a specific pairing mechanism are rare. Here, we observe distinct dependences of the superconducting transition temperature Tc on carrier density n2D for electron gases formed at KTaO3 (111), (001) and (110) interfaces. For the (111) interface, a remarkable linear dependence of Tc on n2D is observed over a range of nearly one order of magnitude. Further, our study of the dependence of superconductivity on gate electric fields reveals the role of the interface in mediating superconductivity. We find that the extreme sensitivity of superconductivity to crystallographic orientation can be explained by pairing via inter-orbital interactions induced by an inversion-breaking transverse optical phonon and quantum confinement. This mechanism is also consistent with the dependence of Tc on n2D. Our study may shed light on the pairing mechanism in other superconducting quantum paraelectrics.

Professional excellence and career advancement in nursing: a conceptual framework for clinical leadership development.

Increasingly, stakeholders in the health care community are recognizing nursing as key to solving the nation's health care issues. This acknowledgment provides a unique opportunity for nursing to demonstrate leadership by developing clinical nurse leaders to collaborate with the multidisciplinary care team in driving evidence-based, safe quality, cost-effective health care services. One approach for nursing success is standardizing the entry-level education for nurses and developing a uniform professional development and career advancement trajectory with appropriate incentives to encourage participation. A framework to guide and provide scientific evidence of how frontline nurses can be engaged will be paramount. The model for professional excellence and career advancement provides a framework that offers a clear path for researchers to examine variables influencing nurses' professional development and career advancement in a systematic manner. Professional Excellence and Career Advancement in Nursing underscores professional preparedness of a registered nurse as central to leadership development. It also describes the elements that influence nurses' participation in professional development and career advancement under 4 main categories emphasizing mentorship and self-efficacy as essential variables.

Origin of the 2D Electron Gas at the SrTiO3 Surface.

Bulk SrTiO3 is a well-known band insulator and the most common substrate used in the field of complex oxide heterostructures. Its surface and interface with other oxides, however, have demonstrated a variety of remarkable behaviors distinct from those expected. In this work, using a suite of in situ techniques to monitor both the atomic and electronic structures of the SrTiO3 (001) surface prior to and during growth, the disappearance and re-appearance of a 2D electron gas (2DEG) is observed after the completion of each SrO and TiO2 monolayer, respectively. The 2DEG is identified with the TiO2 double layer present at the initial SrTiO3 surface, which gives rise to a surface potential and mobile electrons due to vacancies within the TiO2-x adlayer. Much like the electronic reconstruction discovered in other systems, two atomic planes are required, here supplied by the double layer. The combined in situ scattering/spectroscopy findings resolve a number of longstanding issues associated with complex oxide interfaces, facilitating the employment of atomic-scale defect engineering in oxide electronics.

Self-healing Growth of LaNiO3 on a Mixed-Terminated Perovskite Surface.

Developing atomic-scale synthesis control is a prerequisite for understanding and engineering the exotic physics inherent to transition-metal oxide heterostructures. Thus, far, however, the number of materials systems explored has been extremely limited, particularly with regard to the crystalline substrate, which is routinely SrTiO3. Here, we investigate the growth of a rare-earth nickelate─LaNiO3─on (LaAlO3)(Sr2AlTaO6) (LSAT) (001) by oxide molecular beam epitaxy (MBE). Whereas the LSAT substrates are smooth, they do not exhibit the single surface termination usually assumed necessary for control over the interface structure. Performing both nonresonant and resonant anomalous in situ synchrotron surface X-ray scattering during MBE growth, we show that reproducible heterostructures can be achieved regardless of both the mixed surface termination and the layer-by-layer deposition sequence. The rearrangement of the layers occurs dynamically during growth, resulting in the fabrication of high-quality LaNiO3/LSAT heterostructures with a sharp and consistent interfacial structure. This is due to the thermodynamics of the deposition window as well as the nature of the chemical species at interfaces─here, the flexible charge state of nickel at the oxide surface. This has important implications regarding the use of a wider variety of substrates for fundamental studies on complex oxide synthesis.

Elective Cesarean births: are women making emancipated decisions?

This mixed method study investigated the extent to which women used emancipated decision making when selecting a birth method, whether they perceived they had a choice, and if they were satisfied with their decision. Findings suggest that vaginal birth is still the preferred method of delivery for these study participants.

Electric field control of magnon spin currents in an antiferromagnetic insulator.

Pure spin currents can be generated via thermal excitations of magnons. These magnon spin currents serve as carriers of information in insulating materials, and controlling them using electrical means may enable energy efficient information processing. Here, we demonstrate electric field control of magnon spin currents in the antiferromagnetic insulator Cr2O3. We show that the thermally driven magnon spin currents reveal a spin-flop transition in thin-film Cr2O3. Crucially, this spin-flop can be turned on or off by applying an electric field across the thickness of the film. Using this tunability, we demonstrate electric field­induced switching of the polarization of magnon spin currents by varying only a gate voltage while at a fixed magnetic field. We propose a model considering an electric field­dependent spin-flop transition, arising from a change in sublattice magnetizations via a magnetoelectric coupling. These results provide a different approach toward controlling magnon spin current in antiferromagnets.

Two-dimensional superconductivity and anisotropic transport at KTaO3 (111) interfaces.

The distinctive electronic structure found at interfaces between materials can allow unconventional quantum states to emerge. Here we report on the discovery of superconductivity in electron gases formed at interfaces between (111)-oriented KTaO3 and insulating overlayers of either EuO or LaAlO3 The superconducting transition temperature, as high as 2.2 kelvin, is about one order of magnitude higher than that of the LaAlO3/SrTiO3 system. Notably, similar electron gases at KTaO3 (001) interfaces remain normal down to 25 millikelvin. The critical field and current-voltage measurements indicate that the superconductivity is two-dimensional. In EuO/KTaO3 (111) samples, a spontaneous in-plane transport anisotropy is observed before the onset of superconductivity, suggesting the emergence of a distinct "stripe"-like phase, which is also revealed near the critical field.

The relationship of physical function to social integration after stroke.

Stroke is a leading cause of death and a serious long-term disability in this country. Much of the research on stroke rehabilitation has focused on physical/functional recovery as the predominant measure of outcome. There is a gap in knowledge of social issues and integration into societal, family, and community roles after stroke. A descriptive, correlational survey design was used to examine the relationships of functional status, depression, and overall stroke recovery to social integration in a convenience sample of ischemic stroke survivors. The survey response rate was 21.4%. Results showed that functional status, overall stroke recovery, and depression are highly significant predictors of social integration, explaining 62% of the variance (adjusted R2). Comorbid depression was negatively (-.74) and significantly (.01, two-tailed) correlated to social integration, such that higher levels of depression are associated with lower levels of social integration. Finally, employment status after stroke dropped from 48% to 4.2%, and poststroke employment status was correlated to social integration (significance = .03). Care for patients with chronic conditions like stroke should address all domains of the individual-physical, psychosocial, and environmental. Factors including depression and perceptions of overall stroke recovery are significant and should be addressed in the rehabilitation process to better promote social integration. Social integration is an important and understudied aspect of stroke recovery that warrants further research.

Observation of an antiferromagnetic quantum critical point in high-purity LaNiO3.

Amongst the rare-earth perovskite nickelates, LaNiO3 (LNO) is an exception. While the former have insulating and antiferromagnetic ground states, LNO remains metallic and non-magnetic down to the lowest temperatures. It is believed that LNO is a strange metal, on the verge of an antiferromagnetic instability. Our work suggests that LNO is a quantum critical metal, close to an antiferromagnetic quantum critical point (QCP). The QCP behavior in LNO is manifested in epitaxial thin films with unprecedented high purities. We find that the temperature and magnetic field dependences of the resistivity of LNO at low temperatures are consistent with scatterings of charge carriers from weak disorder and quantum fluctuations of an antiferromagnetic nature. Furthermore, we find that the introduction of a small concentration of magnetic impurities qualitatively changes the magnetotransport properties of LNO, resembling that found in some heavy-fermion Kondo lattice systems in the vicinity of an antiferromagnetic QCP.