Bright room temperature single photon source at telecom range in cubic silicon carbide

Single photon emitters (SPEs) play an important role in a number of quantum information tasks such as quantum key distributions. In these protocols, telecom wavelength photons are desired due to their low transmission loss in optical fibers. In this paper, we present a study of bright single-photon emitters in cubic silicon carbide (3C-SiC) emitting in the telecom range. We find that these emitters are photostable and bright at room temperature with a count rate of ~ MHz. Together with the fact that SiC is a growth and fabrication-friendly material, our result may pave the way for its future application in quantum communication technology applications.Comment: Accepted by Nature Communication

Surface acoustic wave driven ferromagnetic resonance in (Ga,Mn)(As,P) epilayers

Interdigitated transducers were used to generate and detect surface acoustic waves on a thin layer of (Ga,Mn)(As,P). The out-of-plane uniaxial magnetic anisotropy of this dilute magnetic semiconductor is very sensitive to the strain of the layer, making it an ideal test material for the dynamic control of magnetization via magneto-striction. The time-domain measurement of the amplitude and phase of the transmitted SAW during magnetic field sweeps indicated a clear resonant behavior at a field close to the one calculated to give a precession frequency equal to the SAW frequency. A resonance was observed from 5K to 85K, just below the Curie temperature of the layer. A full analytical treatment of the coupled magnetization/acoustic dynamics showed that the magneto-strictive coupling modifies the elastic constants of the material and accordingly the wave-vector solution to the elastic wave equation. The shape and position of the resonance were well reproduced by the calculations, in particular the fact that velocity (phase) variations resonated at lower fields than the acoustic attenuation variations

Irreversible magnetization switching using surface acoustic waves

An analytical and numerical approach is developped to pinpoint the optimal experimental conditions to irreversibly switch magnetization using surface acoustic waves (SAWs). The layers are magnetized perpendicular to the plane and two switching mechanisms are considered. In precessional switching, a small in-plane field initially tilts the magnetization and the passage of the SAW modifies the magnetic anisotropy parameters through inverse magneto-striction, which triggers precession, and eventually reversal. Using the micromagnetic parameters of a fully characterized layer of the magnetic semiconductor (Ga,Mn)(As,P), we then show that there is a large window of accessible experimental conditions (SAW amplitude/wave-vector, field amplitude/orientation) allowing irreversible switching. As this is a resonant process, the influence of the detuning of the SAW frequency to the magnetic system's eigenfrequency is also explored. Finally, another - non-resonant - switching mechanism is briefly contemplated, and found to be applicable to (Ga,Mn)(As,P): SAW-assisted domain nucleation. In this case, a small perpendicular field is applied opposite the initial magnetization and the passage of the SAW lowers the domain nucleation barrier.Comment: 11 pages, 4 figure

Quality of life in patients with transcatheter aortic valve implantation: an analysis from the INTERVENT project

BackgroundTranscatheter aortic valve implantation (TAVI) is a standard treatment for patients with aortic valve stenosis due to its very low mortality and complication rates. However, survival and physical integrity are not the only important factors. Quality of life (QoL) improvement is a crucial part in the evaluation of therapy success.MethodsPatients with TAVI were questioned about their QoL before, one month and one year after the intervention as part of the INTERVENT registry trial at Mainz University Medical Center. Three different questionnaires were included in the data collection (Katz ADL, EQ-5D-5l, PHQ-D).ResultsWe included 285 TAVI patients in the analysis (mean age 79.8 years, 59.4% male, mean EuroSCORE II 3.8%). 30-day mortality was 3.6%, complications of any kind occurred in 18.9% of the patients. Main finding was a significant increase in the general state of health measured on the visual analog scale by an average of 4.53 (± 23.58) points (BL to 1-month follow-up, p = 0.009) and by 5.19 (± 23.64) points (BL to 12-month follow-up, p = 0.016). There was also an improvement of depression symptoms, which was reflected in a decrease in the total value of the PHQ-D by 1.67 (± 4.75) points (BL to 12-month follow-up, p = 0.001). The evaluation of the EQ-5D-5l showed a significant improvement in mobility after one month (M = −0.41 (± 1.31), p < 0.001. Regarding the independence of the patients, no significant difference could be found. Apart from that, patients with risk factors, comorbidities or complications also benefited from the intervention despite their poor starting position.ConclusionWe could show an early benefit of QoL in TAVI patients with significant improvement in the subjective state of health and a decrease in symptoms of depression. These findings were consistent over 1 year of follow up

Switching the uniaxial magnetic anisotropy by ion irradiation induced compensation

In the present work, the uniaxial magnetic anisotropy of GaMnAsP is modified by helium ion irradiation. According to the micro-magnetic parameters, e.g. resonance fields and anisotropy constants deduced from ferromagnetic resonance measurements, a rotation of the magnetic easy axis from out-of-plane [001] to in-plane [100] direction is achieved. From the application point of view, our work presents a novel avenue in modifying the uniaxial magnetic anisotropy in GaMnAsP with the possibility of lateral patterning by using lithography or focused ion beam

La spectroscopie de résonance ferromagnétique: fondements et applications

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