Nanowerk December 15, 2023 Negatively charged group-IV color centers in diamond are promising candidates for quantum memories as they combine long storage times with excellent optical emission properties and an optically addressable spin state. However, as a material, diamond lacks the many functionalities needed to realize scalable quantum systems. Thin-film lithium niobate (TFLN), in contrast, offers several useful photonic nonlinearities, including the electro-optic effect, piezoelectricity, and capabilities for periodically poled quasi-phase matching. Researchers at Stanford University have presented highly efficient heterogeneous integration of diamond nanobeams containing negatively charged silicon-vacancy (SiV) centers with TFLN waveguides. They observed greater than 90% transmission […]
Dynamics of skyrmion spin states confirmed in neutron-scattering experiments
Phys.org. November 11, 2023 Some magnetic systems feature spin textures, real-space patterns in the orientation of spins that can topologically form non-trivial configurations. Among them, a vortex-like spin swirling texture known as a magnetic skyrmion has attracted particular attention. Lattices of skyrmions form in the helimagnet MnSi with a periodicity of 18 nm, which makes them amenable to investigation by Lorentz transmission electron microscopy in real space and by small-angle neutron scattering in momentum space. An international team of researchers (Japan, France, Sweden, Czech Republic) examined the low-energy excitations of the skyrmion state in MnSi by using the neutron spin-echo technique […]
Field-induced superconductivity in quantum materials
Phys.org December 12, 2023 Field-induced superconductivity is a rare phenomenon where an applied magnetic field enhances or induces superconductivity. A team of researchers in the US (MIT, Argonne National Laboratory, University of Washington, George Mason University) combined tunable uniaxial stress and applied magnetic field on the ferromagnetic superconductor Eu(Fe0.88Co0.12)2As2 to shift the field-induced zero-resistance temperature between 4 K and a record-high value of 10 K. They used x-ray diffraction and spectroscopy measurements under stress and field to reveal that strain tuning of the nematic order and field tuning of the ferromagnetism act as independent control parameters of the superconductivity. Combining […]
Illuminating the nanoscale: the forceful dance of light and heat
Nanowerk December 13, 2023 Despite its prevalence, the photothermal effect in light-absorbing nanoparticles has typically been assessed using bulk measurements, neglecting near-field effects. Beyond standard imaging and therapeutic uses, nanosecond-transient photothermal effects have been harnessed for bacterial inactivation, neural stimulation, drug delivery, and chemical synthesis. While scanning probe microscopy and electron microscopy offer single-particle imaging of photothermal fields, their slow speed limits observations to milliseconds or seconds, preventing nanoscale dynamic investigations. Researchers at the University of Illinois Urbana-Champaign introduced decoupled optical force nanoscopy (Dofn), enabling nanometer-scale mapping of photothermal forces by exploiting unique phase responses to temporal modulation. They employed […]
In a new light – new approach overcomes long-standing limitations in optics
Nanowerk December 12, 2023 The canonical studies on Mie scattering unravel strong electric/magnetic optical responses in nanostructures, laying foundation for emerging meta-photonic applications. Conventionally, the morphology-sensitive resonances hinge on the normalized frequency, i.e. particle size over wavelength, but non-paraxial incidence symmetry is overlooked. Through confocal reflection microscopy with a tight focus scanning over silicon nanostructures, an international team of researchers (Taiwan, Japan, China) showed the scattering point spread functions’ distinctive spatial patterns featuring linear scattering efficiency was maximal when the focus was misaligned. The underlying physical mechanism was the excitation of higher-order multipolar modes, not accessible by plane wave irradiation, […]
New conductive, cotton-based fiber developed for smart textiles
Science Daily December 11, 2023 Blending conductive fillers with cellulose is the most common means of fiber production. Incorporating a high content of conductive fillers is necessary to achieve desirable conductivity. However, a high filler load deteriorates the processability and mechanical properties of the fibers. Researchers at Washington State University developed wet-spun cellulose-based fibers with a unique side-by-side (SBS) structure via sustainable processing. They engineered sustainable sources (cotton linter and post-consumer cotton waste) and a biocompatible intrinsically conductive polymer (i.e., polyaniline, PANI) into fibers containing two co-continuous phases arranged side-by-side… read more. TECHNICAL ARTICLE
New technique for photon detection
Science Daily December 12, 2023 Currently, all available detectors for detecting long wave infrared (LWIR) light at room temperature operate on amplitude modulation (AM) and are limited in performance by AM noises, including Johnson noise, shot noise, and background fluctuation noise. Researchers at the University of Central Florida have introduced a frequency modulation (FM)-based detection technique , which offers inherent robustness against different types of AM noises. The FM-based approach yields an outstanding room temperature noise equivalent power (NEP), response time, and detectivity (D*). According to the researchers this result promises a novel uncooled LWIR detection scheme that is highly […]
Newly developed material gulps down hydrogen, spits it out, protects fusion reactor walls
Phys.org December 14, 2023 An international team of researchers (USA, South Korea, France, Germany) investigated tantalum (Ta) coating deposited by cold spray technology on 316L stainless steel substrate as a potential plasma-facing material surface. High fluence low energy deuterium plasma irradiation experiments and subsequent thermal annealing cycles associated with thermal desorption spectrometry (TDS) demonstrated superior structural stability of the Ta coating. TDS experiments revealed the outgassing of deuterium (as measure of its retention) for cold spray Ta coatings to be three times higher than bulk Ta and two orders of magnitude greater than bulk polycrystalline W. X-ray photoelectron spectroscopy revealed […]
Physicists discover new quantum phases in low-dimensional polar systems
Phys.org December 13, 2023 Quantum fluctuations (QFs) caused by zero-point phonon vibrations (ZPPVs) are known to prevent the occurrence of polar phases in bulk incipient ferroelectrics down to 0 K. On the other hand, little is known about the effects of QFs on the recently discovered topological patterns in ferroelectric nanostructures. A team of researchers in the US (University of Arkansas, Fayetteville, Lonestar College, Texas) has shown how QFs affect the topology of several dipolar phases in ultrathin Pb(Zr0.4Ti0.6)O3 (PZT) films. They showed that the ZPPVs do not suppress polar patterns but rather stabilize the labyrinth, bimeron and bubble phases within […]
Researchers achieve chemically controlled, reversible magnetic phase transition
Phys.org November 10, 2023 Researchers in China proposed a chemical means to reversibly control spin order of lactim–lactam tautomerization to reversibly modulate the magnetic phase transition in 2D organometallic lattices. They theoretically verified the proposal by designing several 2D organometallic frameworks with antiferromagnetic to ferrimagnetic spin order transformation modulated by lactim–lactam tautomerization on organic linkers. The transition originated from the change in spin states of organic linkers (from singlet to doublet) via tautomerization. Such a transition further switched materials’ electronic structures from normal semiconductors with zero spin polarization to bipolar magnetic semiconductors with valence and conduction band edges 100% spin […]