February 2025

Researchers from China's Tianjin University, Fudan University, University of Chinese Academy of Sciences, National Center for Nanoscience and Technology and Tsinghua University have introduces a new technique, called the "Wax-aided immersion method," to produce controllable chiral graphene rolls. This advancement provides a novel approach to chirality modulation in two-dimensional materials and their potential applications in spintronics, laying a foundation for future developments in quantum computing and spintronic devices.

Chirality refers to the property of objects whose mirror images cannot be perfectly superimposed, much like the relationship between a person's left and right hands. Chirality is omnipresent in nature, from molecules to materials, and chiral structures often exhibit unique optical, electronic, and chemical properties. For example, the biological activity of many drug molecules differs significantly based on their chirality. In materials science, the development of chiral materials is crucial for advancing frontier technologies such as optical devices, spintronics, and quantum computing.

Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory and the University of Washington have reported a new technique that could help advance the development of quantum technology. Their innovation, surface-sensitive spintronic terahertz spectroscopy (SSTS), provides an unprecedented look at how quantum materials behave at interfaces.

With the SSTS technique, a laser pulse is applied to one side of an oxide/metal sample and terahertz radiation is emitted. From the signal, the dynamics of the TO1 surface phonon is detected in the oxide at its interface with the metal. (Image by Argonne National Laboratory.)
 

“This technique allows us to study surface phonons — the collective vibrations of atoms at a material’s surface or interface between materials,” said Zhaodong Chu, a postdoctoral researcher at Argonne and first author of the study. ​“Our findings reveal striking differences between surface phonons and those in the bulk material, opening new avenues for research and applications.”

Researchers from ICN2, ICMAB-CSIC and the Bulgarian Academy of Science have shown how the interaction with palladium diselenide (PdSe₂) can modify and enhance graphene’s spintronic performance. The team's finding improve existing understanding of spin dynamics in graphene-based van der Waals heterostructures and could be key for developing more efficient computing devices.

Van der Waals heterostructures are materials formed by combining layers of different ultra-thin materials stacked on top of each other. In recent years, these structures have proven to be very useful for studying and understanding unusual physical phenomena, making them promising candidates for the development of new technologies. The new study analyzed the interactions that occur in a graphene and palladium diselenide (PdSe₂) heterostructure. The team stresses: "Our results showed that PdSe₂ can induce significant changes in the spin transport properties and dynamics of graphene, providing new possibilities for controlling information-carrying spin currents”. These findings constitute an important step forward in elucidating spin physics in van der Waals heterostructures and could allow for spin-logic devices in the future.

Tohoku University researchers have observed an opto-magnetic torque approximately five times more efficient than in conventional magnets. This breakthrough could be extremely beneficial for the development of light-based spin memory and storage technologies.

Opto-magnetic torque is a method which can generate force on magnets, which can be used to change the direction of magnets by light more efficiently. By creating alloy nanofilms with up to 70% platinum dissolved in cobalt, the team discovered that the unique relativistic quantum mechanical effects of platinum significantly boost the magnetic torque.

While most multiferroics can't operate above room temperature, a team of researchers at Tohoku University demonstrated that terbium oxide Tb₂(MoO₄)₃ works as a multiferroic even at 160°C.

A material that loses its functionality due to heat (from the environment or generated by the device itself) has limited practical applications. This is the major Achilles heel of multiferroics—materials that possess close coupling between magnetism and ferroelectricity. This coupling makes multiferroics an attractive area of research, despite that weakness.