Researchers discover a potential application of unwanted electronic noise in semiconductors

Researchers from Korea's Institute for Basic Science (IBS), China's National University of Defense Technology and Harvard University in the U.S have made a fascinating breakthrough that can potentially harness fluctuations in semiconductors caused by Random Telegraph Noise (RTN), a type of unwanted electronic noise that has long been a nuisance in electronic systems.

Led by Professor Lee Young Hee from IBS, the team reported that magnetic fluctuations and their gigantic RTN signals can be generated in a vdW-layered semiconductor by introducing vanadium in tungsten diselenide (V-WSe2) as a minute magnetic dopant. 

Read the full story Posted: Aug 13,2023

Researchers develop atomic-scale spin-optical laser

Researchers from the Technion – Israel Institute of Technology, Tel Aviv University and China's Shanghai Jiao Tong University have developed a coherent and controllable spin-optical laser based on a single atomic layer. This was enabled by coherent spin-dependent interactions between a single atomic layer and a laterally confined photonic spin lattice, the latter of which supports high-Q spin-valley states through the photonic Rashba-type spin splitting of a bound state in the continuum.

The team's achievement could pave the way towards studying coherent spin-dependent phenomena in both classical and quantum regimes, opening new horizons in fundamental research and optoelectronic devices exploiting both electron and photon spins.

Read the full story Posted: Aug 08,2023

Researchers report anomalous dynamics of non-collinear antiferromagnets

Researchers from MIT and Tohoku University have reported a representative effect of the anomalous dynamics at play when an electric current is applied to a class of magnetic materials called non-collinear antiferromagnets. 

Non-collinear antiferromagnets have properties distinct from conventional magnetic materials—in traditional collinear magnets, the magnetic moments align in a collinear fashion. However, in non-collinear ones, the moments form finite angles between one another. Scientists describe these non-collinear arrangements as a single order parameter, the octupole moment, which has been demonstrated to be critical for determining the exotic properties of the materials.

Read the full story Posted: Aug 06,2023

Researchers develop method to manipulate solid-state spin concentration through charge transport

Researchers from MIT, Princeton University and Politecnico di Milano have found a way to tune the spin density in diamonds by applying an external laser or microwave beam. These findings could open new possibilities for advanced quantum devices.

Spin defects make crystalline materials highly useful for quantum-based devices such as ultrasensitive quantum sensors, quantum memory devices, or systems for simulating the physics of quantum effects. Varying the spin density in semiconductors can lead to new properties in a material, but this density is usually fleeting and elusive, thus hard to measure and control locally. Now, the team of researchers has found a way to tune the spin density in diamonds, changing it by a factor of two, by applying an external laser or microwave beam. 

Read the full story Posted: Aug 05,2023

Researchers report unusual motion across a layered magnetic material tied to changing its electron spin

A team of researchers from the DOE/Argonne National Laboratory and U.S. additional laboratories and universities have reported a mechanical response across a layered magnetic material tied to changing its electron spin. This response could have important applications in nanodevices requiring ultra-precise and fast motion control.

A little over a century ago, physicists Albert Einstein and Wander de Haas reported a surprising effect in ferromagnets: if you suspend an iron cylinder from a wire and expose it to a magnetic field, it will start rotating if you simply reverse the direction of the magnetic field. "Einstein and de Haas's experiment is almost like a magic show," said Haidan Wen, a physicist in the Materials Science and X-ray Science divisions of the U.S. Department of Energy's (DOE) Argonne National Laboratory. ​"You can cause a cylinder to rotate without ever touching it."

Read the full story Posted: Aug 03,2023

Researchers get a better idea of the interplay between a molecule’s electrons and nuclei

Researchers from Northwestern University and North Carolina State University have gained fascinating insights into the relationship between the spin-vibronic effect and intersystem crossing in molecules. The work could lead to new ways to control electron spin within molecules, and to more efficient energy capture that could be applied to various fields. 

The team presented coherence spectroscopy experiments that reveal the interplay between the spin, electronic and vibrational degrees of freedom that drive efficient singlet–triplet conversion in four structurally related dinuclear Pt(II) metal–metal-to-ligand charge-transfer (MMLCT) complexes. Photoexcitation activates the formation of a Pt–Pt bond, launching a stretching vibrational wavepacket. The molecular-structure-dependent decoherence and recoherence dynamics of this wavepacket resolve the spin–vibronic mechanism.

Read the full story Posted: Jul 30,2023

Researchers synthesize highly-ordered topological semimetal thin films via sputtering technology

A team of scientists from the University of Minnesota Twin Cities has synthesized a thin film of a unique topological semimetal material that has the potential to generate more computing power and memory storage while using significantly less energy. The researchers were also able to closely study the material, leading to some fascinating findings about the physics behind its unique properties.

Much attention is put into developing the materials that power electronic devices. While traditional semiconductors are the technology behind most of today's computer chips, scientists are always looking for new materials that can generate more power with less energy to make electronics better, smaller, and more efficient. One such candidate for these new and improved computer chips is a class of quantum materials called topological semimetals. The electrons in these materials behave in different ways, giving the materials unique properties that typical insulators and metals used in electronic devices do not have. For this reason, they are being explored for use in spintronic devices, an alternative to traditional semiconductor devices that leverage the spin of electrons rather than the electrical charge to store data and process information.

Read the full story Posted: Jul 15,2023

Researchers investigate magnetic interactions in a Kagome layered topological magnet

A research team from Ames National Laboratory, National Institute of Standards and Technology (NIST), University of California Santa Barbara (UCSB), Iowa State University, University of Edinburgh, George Mason University and Oak Ridge National Laboratory (ORNL) recently conducted an investigation of the magnetism of TbMn6Sn6, a Kagome layered topological magnet. They found that the magnetic spin reorientation in the material occurs by generating increasing numbers of magnetically isotropic ions as the temperature increases.

Rob McQueeney, a scientist at Ames Lab and project lead, explained that TbMn6Sn6 has two different magnetic ions in the material, terbium and manganese. The direction of the manganese moments controls the topological state, "But it's the terbium moment that determines the direction that the manganese points," he said. "The idea is, you have these two magnetic species and it is the combination of their interactions which controls the direction of the moment."

Read the full story Posted: Jul 11,2023

Researchers detect pair density wave state in UTe2

Scientists at Cornell University, Washington University in St. Louis and University of Maryland have revealed a new phase of matter in candidate topological superconductors that could have significant consequences for condensed matter physics and for the field of quantum computing and spintronics.

The researchers discovered and visualized a crystalline yet superconducting state in a new and unusual superconductor, Uranium Ditelluride (UTe2), using one of the world’s most powerful millikelvin Scanned Josephson Tunnelling Microscopes (SJTM). This “spin-triplet electron-pair crystal” is a previously unknown state of topological quantum matter.

Read the full story Posted: Jul 10,2023

Researchers develop way to use perovskite materials and light to control electron spins

Researchers from Cambridge University in the UK, Korea's DGIST and Harvard University in the U.S have shown that electron spins could become more efficient and easier to manage through a light-based approach using halide perovskite semiconductors. The team observed ultrafast spin-domain formation in polycrystalline halide perovskite thin films in response to irradiating the films with circularly polarized light at room temperature.

Photoinduced spin-charge interconversion in semiconductors, with spin-orbit coupling, could provide a route to spintronics that does not require external magnetic fields, which tend to be challenging to control. An electron can have two spin states, up or down, and these states can be used to store and process information. But manipulating spin states can be tricky, requiring the use of magnetic fields on perfectly ordered materials at extremely low temperatures to work.

Read the full story Posted: Jul 06,2023