| 1. |
|
|
| 2. |
|
|
| 3. |
- Bray, C., et al.
(författare)
-
Temperature-dependent zero-field splittings in graphene
- 2022
-
Ingår i: Physical Review B. - 2469-9969 .- 2469-9950. ; 106:24
-
Tidskriftsartikel (refereegranskat)abstract
- Graphene is a quantum spin Hall insulator with a 45μeV-wide nontrivial topological gap induced by the intrinsic spin-orbit coupling. Even though this zero-field spin splitting is weak, it makes graphene an attractive candidate for applications in quantum technologies, given the resulting long spin-relaxation time. On the other side, the staggered sublattice potential, resulting from the coupling of graphene with its boron nitride substrate, compensates intrinsic spin-orbit coupling and decreases the nontrivial topological gap, which may lead to the phase transition into trivial band insulator state. In this work, we present extensive experimental studies of the zero-field splittings in monolayer and bilayer graphene in a temperature range 2-12 K by means of subterahertz photoconductivity-based electron spin-resonance technique. Surprisingly, we observe a decrease of the spin splittings with increasing temperature. We discuss the origin of this phenomenon by considering possible physical mechanisms likely to induce a temperature dependence of the spin-orbit coupling. These include the difference in the expansion coefficients between the graphene and the boron nitride substrate or the metal contacts, the electron-phonon interactions, and the presence of a magnetic order at low temperature. Our experimental observation expands knowledge about the nontrivial topological gap in graphene.
|
|
| 4. |
- Kosydar-Bochenek, J, et al.
(författare)
-
The Perception of the Patient Safety Climate by Health Professionals during the COVID-19 Pandemic-International Research
- 2022
-
Ingår i: International journal of environmental research and public health. - : MDPI AG. - 1660-4601. ; 19:15
-
Tidskriftsartikel (refereegranskat)abstract
- The patient safety climate is a key element of quality in healthcare. It should be a priority in the healthcare systems of all countries in the world. The goal of patient safety programs is to prevent errors and reduce the potential harm to patients when using healthcare services. A safety climate is also necessary to ensure a safe working environment for healthcare professionals. The attitudes of healthcare workers toward patient safety in various aspects of work, organization and functioning of the ward are important elements of the organization’s safety culture. The aim of this study was to determine the perception of the patient safety climate by healthcare workers during the COVID-19 pandemic. Methods: The study was conducted in five European countries. The Safety Attitude Questionnaire (SAQ) short version was used for the study. A total of 1061 healthcare workers: physicians, nurses and paramedics, participated in this study. Results: All groups received the highest mean results on the stress recognition subscale (SR): nurses 98.77, paramedics 96.39 and physician 98.28. Nurses and physicians evaluated work conditions (WC) to be the lowest (47.19 and 44.99), while paramedics evaluated perceptions of management (PM) as the worst (46.44). Paramedics achieved statistically significantly lower scores compared to nurses and physicians in job satisfaction (JS), stress recognition (SR) and perception of management (PM) (p < 0.0001). Paramedics compared to nurses and physicians rank better in working conditions (WC) in relation to patient safety (16.21%). Most often, persons of lower seniority scored higher in all subscales (p = 0.001). In Poland, Spain, France, Turkey, and Greece, healthcare workers scored highest in stress recognition (SR). In Poland, Spain, France, and Turkey, they assessed working conditions (WC) as the worst, while in Greece, the perception of management (PM) had the lowest result. Conclusion: Participant perceptions about the patient safety climate were not at a particularly satisfactory level, and there is still a need for the development of patient safety culture in healthcare in Europe. Overall, positive working conditions, good management and effective teamwork can contribute to improving employees’ attitudes toward patient safety. This study was carried out during the COVID-19 pandemic and should be repeated after its completion, and comparative studies will allow for a more precise determination of the safety climate in the assessment of employees.
|
|
| 5. |
- Maussang, K., et al.
(författare)
-
Temperature dependance of Intrinsic Spin Orbit Coupling Gap in Graphene probed by Terahertz photoconductivity
- 2023
-
Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035.
-
Konferensbidrag (refereegranskat)abstract
- Graphene is a quantum spin Hall insulator, with a nontrivial topological gap induced by the spin-orbit coupling. Such splitting is weak (∼ 45 μ eV) in the absence of external magnetic field. However, due to rather long spin-relaxation time, graphene is an attractive candidate for applications in quantum technologies. When it is encapsulated in hexagonal boron nitride, the coupling between graphene and the substrate compensates intrinsic spin-orbit coupling and decreases the nontrivial topological gap, which may lead to phase transition into a trivial band insulator state. In this work, we have measured experimentally the zero-field splittings in monolayer and bilayer graphene by the means of subterahertz photoconductivity-based electron spin resonance technique. The dependance in temperature of such splittings have been also studied in the 2-12K range. We observed a decrease of the spin splittings with increasing temperature. Such behavior might be understood from several physical mechanisms that could induce a temperature dependence of the spin-orbit coupling. These includes the difference in the expansion coefficients between the graphene and the boron nitride substrate or the metal contacts, the electronphonon interactions, and the presence of a magnetic order at low temperature.
|
|
| 6. |
- Rehman, A., et al.
(författare)
-
Generation-recombination and 1/f noise in carbon nanotube networks
- 2021
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 118:24
-
Tidskriftsartikel (refereegranskat)abstract
- The low-frequency noise is of special interest for carbon nanotubes devices, which are building blocks for a variety of sensors, including radio frequency and terahertz detectors. We studied noise in as-fabricated and aged carbon nanotube networks (CNNs) field-effect transistors. Contrary to the majority of previous publications, as-fabricated devices demonstrated the superposition of generation-recombination (GR) and 1/f noise spectra at a low-frequency range. Although all the devices revealed identical current-voltage characteristics, GR noise was different for different transistors. This effect is explained by the different properties and concentrations of trap levels responsible for the noise. Unexpectedly, exposure of these devices to the atmosphere reduced both the resistance and GR noise due to nanotube's p-doping by adsorbed water molecules from the ambient atmosphere. The presence of the generation recombination noise and its dependences on the environment provides the basis for selective gas sensing based on the noise measurements. Our study reveals the noise properties of CNNs that need to be considered when developing carbon nanotubes-based selective gas sensors.
|
|
