Phys.org October 25, 2024 The ocean annually absorbs about a quarter of all anthropogenic carbon dioxide (CO2) emissions. Global estimates of air–sea CO2 fluxes are typically based on bulk measurements of CO2 in air and seawater and neglect the effects of vertical temperature gradients near the ocean surface. Theoretical and laboratory observations indicate that these gradients alter air–sea CO2 fluxes, because the air–sea CO2 concentration difference is highly temperature sensitive. However, in situ field evidence supporting their effect is so far lacking. An international team of researchers (UK, the Netherlands) presented independent direct air–sea CO2 fluxes alongside indirect bulk fluxes […]
Specially designed transistors allow researchers to ‘hear’ defects in a promising nanomaterial
Phys.org October 22, 2024 Single-crystal hexagonal boron nitride (hBN) is used extensively in many two-dimensional electronic and quantum devices, where defects significantly impact performance. An international team of researchers (Norway, Germany) examined the capture and emission dynamics of defects in hBN by utilizing low-frequency noise (LFN) spectroscopy in hBN-encapsulated and graphene-contacted MoS2 field-effect transistors (FETs). The low disorder of this heterostructure allowed the detection of random telegraph signals (RTS) in large device dimensions of 100 μm2 at cryogenic temperatures. Analysis of gate bias- and temperature-dependent LFN data indicated that RTS originated from a single trap species within hBN. Through calculations […]
Successful experiment paves the way for discovery of a new element
Phys.org October 22, 2024 An international team of researchers (USA – Lawrence Berkeley National Laboratory, San Jose State University, Oregon State University, Lawrence Livermore National Laboratory, Texas A&M University, UC Berkeley, Oak Ridge National Laboratory, Argonne National Laboratory, Sweden, France, UK, Switzerland) tested a new method for observing the element livermorium, which has 116 protons in its atomic nucleus. The superheavy elements first required an accelerator to deliver an intense ion beam, which was then focused onto a target. The target consisted of a thin layer of an element heavier than uranium. The product formed during the fusion reaction could […]
Variations in scientific ethics: Chinese scientists prioritize government service more than global peers
Phys.org October 31, 2024 A team of researchers in the US (Santa Clara University, Rice University) used a dataset comprising 211 interviews with scientists working in China, the United States, and the United Kingdom to explain whether and in what manner physicists conceptualize scientific ethics within a global or national framework. The empirical findings brought to light disparities across nations in the physicists’ perceptions of what constituted responsible mentorship and engagement in public service. The cross-national variations underscored the moral agency of physicists as they navigated the ethical standards embraced by the global scientific community vis-à-vis those that are specific […]
Top 10 Science and Technology Inventions for the Week of October 25, 2024
01. Towards better solar cells: Exploring an anomalous phenomenon of electricity generation 02. All-optical switch device paves way for faster fiber-optic communication 03. Engineers unlock lithium from extreme environments 04. Graphene-based memristors move a step closer to benefiting next-generation computing 05. Magnetic octupoles help overcome problems with antiferromagnets 06. A multi-level breakthrough in optical computing—a faster, more efficient, and robust memory cell 07. New electrochemical water splitting method offers fast, sustainable method for hydrogen production 08. Researchers reveal quantum advantage that could advance future sensing devices 09. Silicon metasurfaces unlock broad-spectrum infrared imaging 10. Gold structures improve spin wave transfer […]
All-optical switch device paves way for faster fiber-optic communication
Phys.org October 19, 2024 Optical Stark effect is an example of using Floquet engineering for optical trapping of atoms and breaking time-reversal symmetry in solids. However, floquet engineering typically requires high field intensities obtained in ultrafast pulses, severely limiting its use. An international team of researchers (USA – University of Michigan, Japan, Taiwan) demonstrated using cavity engineering of the vacuum modes to achieve Floquet effects at an extremely low fluence of 450 photons/μm2. At higher fluences, the cavity-enhanced Floquet effects led to 50 meV spin and valley splitting of WSe2 excitons, corresponding to an enormous time-reversal breaking. They demonstrated an […]
Amorphous nanosheets created using hard-to-synthesize metal oxides and oxyhydroxides
Phys.org October 21, 2024 Amorphous 2D nanosheets have unique properties that are distinct from crystalline 2D nanosheets. However, compared with the vast library of crystalline 2D nanosheets, amorphous 2D nanosheets lack an efficient synthetic approach. Researchers in Japan developed a strategy that yields a library of 10 distinct amorphous 2D metal oxides/oxyhydroxides using solid-state surfactant crystals. A key feature of this process was a stepwise reaction using solid surfactant. The solid-state surfactant crystals have metal ions arranged in the interlayer space, and hydrolysis of the metal ions leads to the formation of isolated clusters in the surfactant crystals via limited […]
The corners where atoms meet may provide a path to new materials for extreme conditions
Phys.org October 16, 2024 A team of researchers in the US (George Washington University, George Mason University, Lawrence Berkeley University, Johns Hopkinson University, Sandia National Laboratory, Leigh University) presented large-scale atomistic simulations that revealed triple junction (TJ) segregation in Pt–Au nanocrystalline alloys in agreement with experimental observations. While existing studies suggested grain boundary solute segregation as a route to thermally stabilize nanocrystalline materials with respect to grain coarsening, the researchers quantitatively showed that it was specifically the segregation to TJs that dominated the observed stability of the alloys. The results showed that doping the TJs made them immobile, thereby locking […]
Engineers unlock lithium from extreme environments
Phys.org October 22, 2024 In contrast to the predominant production of lithium from hard rock, lithium extraction from brine sources has proven more economical and sustainable. However, the low efficiency of the extraction process, complex composition and poor selectivity against magnesium, are the major competing species. Researchers in Australia showed a loose nanofiltration process involving ethylenediaminetetraacetic acid (EDTA) for direct and efficient Li+ extraction as well as effective Mg2+ utilization from salt-lake brines. Taking advantage of selective binding between EDTA4− and Mg2+, their process achieved ultrahigh Mg2+ rejection of 99.85%, ultrafast Li+ flux and unprecedented Li+/Mg2+ separation factor under industrial […]
Gold structures improve spin wave transfer to address electronics overheating problem
Phys.org October 22, 2024 To realize magnonic devices, finding a way to make magnons better transport and efficiently pump their spin angular momentum across a ferromagnetic insulator (FMI)/normal metal interface is crucial. An international team of researchers (South Korea, Japan) found that modulating the magnon temperature in the FMI led to significantly enhanced spin pumping. The modulation was achieved by careful interfacial engineering via a nanoscale thermal fin structure that strengthened the energy exchange between magnons and phonons across interfaces. Theoretical and experimental evidence coherently indicated that the observed enhancement was due to modified magnon temperature profile in the FMI. […]