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Category: materials

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.

Physicists discover what controls the speed of quantum time

From the article:

…in copper, the transition was extremely fast, taking about 26 attoseconds.

In the layered materials TiSe₂ and TiTe₂, the same process slowed to between 140 and 175 attoseconds. In CuTe, with its chain-like structure, the transition exceeded 200 attoseconds. These findings show that the atomic scale shape of a material strongly affects how quickly a quantum event unfolds, with lower symmetry structures leading to longer transition times.

Time may feel smooth and continuous, but at the quantum level it behaves very differently. Physicists have now found a way to measure how long ultrafast quantum events actually last, without relying on any external clock. By tracking subtle changes in electrons as they absorb light and escape a material, researchers discovered that these transitions are not instantaneous and that their duration depends strongly on the atomic structure of the material involved.

Muon Knight shift reveals the behavior of superconducting electron pairs

Quantum materials and superconductors are difficult enough to understand on their own. Unconventional superconductors, which cannot be explained within the framework of standard theory, take the enigma to an entirely new level. A typical example of unconventional superconductivity is strontium ruthenate, SRO214, the superconductive properties of which were discovered by a research team that included Yoshiteru Maeno, who is currently at the Toyota Riken—Kyoto University Research Center.

The findings are published in the journal Physical Review Letters.

Debate over SRO214’s superconducting nature.

Pulsar timing hints at a nearby dark matter ‘sub-halo’

A group of US astronomers may have uncovered the first evidence for a dark matter sub-halo lurking just beyond our stellar neighborhood. Reporting their findings in Physical Review Letters, a team led by Sukanya Chakrabarti at the University of Alabama in Huntsville suggests that an unseen clump of dark matter could be subtly tugging on nearby pulsars. If confirmed, the result could shed new light on the elusive nature of dark matter and how it is distributed throughout our galaxy.

Despite never having been observed directly, astronomers estimate that dark matter makes up around 85% of the total mass of the universe. According to the best available cosmological models, this invisible material forms vast, diffuse “halos” that completely envelop the flat disks of galaxies like the Milky Way. These halos, in turn, should be populated by numerous smaller structures known as dark matter sub-halos.

If theoretical predictions are correct, such sub-halos should be abundant throughout the galaxy. Yet even with masses potentially exceeding tens of millions of times that of the sun, their limited gravitational influence on visible matter has so far made them extraordinarily difficult to detect.

Novel electronic structures and magnetic properties in twisted two-dimensional graphene/Janus 2H–VSeTe heterostructures

In the experiments, the stacking of other layers can be stacked layer by layer by using the method of direct growth, such as chemical bath deposition [17] and chemical vapor deposition [18]. To date, many vertical stacking structures based on graphene have been explored, such as graphene/Janus 2H-VSeTe [19], graphene/Janus 2H-VSeX (X = S, Te) [20], graphene/WTe2, etc. Scientists have done a lot of research on heterostructures, from the aspects of spin-orbital coupling [21], strains, applied electric field and Lattice mismatch, etc.

Show abstract.

Uncovering hidden quantum landscapes

Imagine trying to read Braille while wearing thick winter gloves; you might feel the general shape of the book, but the story remains a mystery. For decades, this has been the reality for physicists trying to “feel” the invisible energy landscapes that govern how electrons move in quantum materials. Now, researchers at the Weizmann Institute of Science have taken the gloves off.

A single atomic defect acts as a new type of microscope to reveal the electrostatic potential landscape steering the behavior of electrons in quantum materials. (Image: Weizmann Institute of Science)

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