July 2023

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.

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.

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."

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.

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.