Small rotations of a graphene layer relative to its neighboring layer expose previously unseen topological phases.
Category: materials
Major earthquakes are just as random as smaller ones
For obvious reasons, it would be useful to predict when an earthquake is going to occur. It has long been suspected that large quakes in the Himalayas follow a fairly predictable cycle, but nature, as it turns out, is not so accommodating. A new study published in the journal Science Advances shows that massive earthquakes are just as random as small ones. A team of researchers led by Zakaria Ghazoui-Schaus at the British Antarctic Survey reached this conclusion after analyzing sediments from Lake Rara in Western Nepal.
The team extracted a 4-meter-long tube from the bottom of the lake and identified 50 sediment layers spanning 6,000 years. Whenever a major quake shakes the region, underwater landslides create layers of sediment called turbidites. These deposits are characterized by coarse materials that settle first, followed by sand, then silt and finally clay. Each layer is essentially a snapshot of an individual earthquake, although they can also result from floods and slope failures.
To confirm that these layers were caused by quakes, the team compared them with modern records and computer models. They concluded that only a quake of magnitude 6.5 or higher could trigger underwater landslides. Radiocarbon dating of organic material within each layer revealed roughly when each of the major quakes occurred.
Scientists reveal formation mechanism behind spherical assemblies of nanocrystals
From table salt to snowflakes, and from gemstones to diamonds—we encounter crystals everywhere in daily life, usually cubic (table salt) or hexagonal (snowflakes). Researchers from Noushine Shahidzadeh’s group at the UvA Institute of Physics now demonstrate how mesmerizing spherical crystal shapes arise through structures called spherulites.
A new study done in Shahidzadeh’s lab at the Institute of Physics / Van der Waals Zeeman-Institute, reveals how neatly ordered (hemi-) spherical or pancake-like structures in nature can emerge from completely disordered salt solutions. Moreover, scientists can now harness these structures to create advanced materials. The work is published in the journal Communications Chemistry.
Making In Vivo Progress in CAR Therapeutic Development
As scientists work toward moving in vivo CAR methods from concept to clinic, they must ensure that complex, multistep discovery and development workflows yield reliable and biologically meaningful data. In this article, learn more about materials for in vivo CAR discovery and development.
Learn more in this new issue of the TS Digest.
In vivo gene delivery, precise immune profiling, and robust quality controls reshape how researchers develop the next generation of CAR therapies.
A simple discovery is shaking the foundations of spintronics
A long-standing mystery in spintronics has just been shaken up. A strange electrical effect called unusual magnetoresistance shows up almost everywhere scientists look—even in systems where the leading explanation, spin Hall magnetoresistance, shouldn’t work at all. Now, new experiments reveal a far simpler origin: the way electrons scatter at material interfaces under the combined influence of magnetization and an electric field.
Anomalous magnetoresistance emerges in antiferromagnetic kagome semimetal
Researchers from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences (CAS), in collaboration with researchers from the Institute of Semiconductors of CAS, revealed anomalous oscillatory magnetoresistance in an antiferromagnetic kagome semimetal heterostructure and directly identified its corresponding topological magnetic structures. The results are published in Advanced Functional Materials.
Antiferromagnetic kagome semimetals, characterized by a strong interplay of geometric frustration, spin correlations, and band topology, have emerged as a promising platform for next-generation antiferromagnetic topological spintronics.
In this study, the researchers fabricated an FeSn/Pt heterostructure based on an antiferromagnetic kagome semimetal. By breaking inversion symmetry at the interface, the researchers introduced and tuned the Dzyaloshinskii-Moriya interaction, enabling effective control of spin configurations in the FeSn layer.
When heat flows backwards: A neat solution for hydrodynamic heat transport
When we think about heat traveling through a material, we typically picture diffusive transport, a process that transfers heat from high-temperature to low-temperature as particles and molecules bump into each other, losing kinetic energy in the process. But in some materials, heat can travel in a different way, flowing like water in a pipeline that—at least in principle—can be forced to move in a direction of choice. This second regime is called hydrodynamic heat transport.
Heat conduction is mediated by movement of phonons, which are collective excitations of atoms in solids, and when phonons spread in a material without losing their momentum in the process, you have phonon hydrodynamics.
The phenomenon has been studied theoretically and experimentally for decades, but is becoming more interesting than ever to experimentalists because it features prominently in materials like graphene, and could be exploited to guide heat flow in electronics and energy storage devices.
MIT Scientists Shrink Terahertz Light To Reveal Hidden Quantum “Jiggles”
The kind of light you use can reveal very different things about a material. Visible light mainly shows what is happening at the surface. X-rays can probe structures inside. Infrared light highlights the heat a material gives off.
Researchers at MIT have now turned to terahertz light to uncover quantum vibrations in a superconducting material, signals that scientists have not been able to observe directly until now.