New materials and techniques hold promise for microelectronics and quantum technologies

As the size of phones and computers decreases, our needs for data storage and transfer increase. Electronic devices have been powered by semiconductors for decades, but as the trend toward miniaturization continues, there is a limit to how small semiconductors can be manufactured.

The next generation of wearable devices requires a new solution. Spintronics, or spin electronics, is a revolutionary new field of condensed matter physics that can increase the memory and logic processing capacity of nanoelectronic devices while reducing energy consumption and production costs. This is achieved by using inexpensive materials and the magnetic properties of an electron’s spin to perform memory and logic functions instead of using the flow of electronic charge used in typical electronics.

New work by scientists at Florida State University advances spintronics research.

Professors Biwu Ma of the Department of Chemistry and Biochemistry and Peng Xiong of the Department of Physics are working with low-dimensional organic metal halide hybrids, a new class of hybrid materials capable of powering optoelectronic devices such as solar cells, light-emitting diodes or LEDs. and photodetectors.

Together, they identified new magnetic and electronic properties in these materials, pointing to impressive potential in spintronics. Xiong, in his solo work, designed the first example of magnetless electronic spin generation in a semiconductor, facilitating the low-cost development of high-power electronic devices.

“Although this new class of materials has proven useful in creating optical materials for optoelectronic devices, such as LEDs, this is the first time we have observed unique magnetic properties,” said Ma, an expert in chemical chemistry. materials.

“Depending on the choices of suitable organic components and metal halides, which could theoretically be unlimited, we are able to assemble them into crystal structures of different dimensions. Different compositions and structures cause them to exhibit diverse properties, which can have a variety of applications, ranging from optoelectronics to spintronics, and even a combination of the two.”

Ma’s lab synthesizes materials in various configurations before sending them to Xiong’s lab for electronic and magnetic characterizations. Graduate students from both labs direct the experiments. Xiong’s laboratory then provides information on the properties of the synthesized materials.

In the study titled “Antiferromagnetic Ordering in A One-Dimensional Organic Copper Chloride Hybrid Insulator,” published in Modified chemistryMa and Xiong unveil newly discovered properties, highlighting the potential of these materials as a highly tunable quantum platform for spintronics.

“It’s exciting to think that this is just a publication done on a specific material,” said Ma. “We are synthesizing hundreds of materials and we hope to see more interesting useful properties and applications emerge in the future.”

Research teams led by Bin Ouyang, associate professor of chemistry and biochemistry at FSU, and Dali Sun, associate professor of physics at North Carolina State University, also contributed to this research.

“The collaboration between Biwu and myself is very natural,” Xiong said of the four-year-old partnership. “There’s a lot of back and forth in terms of feedback between materials synthesis and property characterization in both labs, what we need to refine in synthesis to get optimal properties and much more. It’s highly interactive and we have many different interactions. projects happening at the same time with different materials.

While the duo’s collaborative research focuses on developing new functional materials for use in spintronics, Xiong’s individual research introduces an entirely new way to power spintronics by exploiting the interaction of an electron’s spin with the chirality of its environment to produce electron spin without a magnet in a semiconductor. .

Currently, spin generation is usually created by interaction with a magnet, and such schemes have significant drawbacks. For example, marginal fields from external magnets can easily disrupt spin alignment, leading to complications if multiple semiconductors are used in a small electronic device such as a high-density computer chip.

In a study titled “Chirality-Induced Magnet-Free Spin Generation in a Semiconductor,” published in Advanced materials This summer, Xiong demonstrates a non-magnetic route of spin generation.

“Instead of applying a voltage to the magnet to move the electron in and out of the semiconductor, we reverse the spin of the transiting electron,” Xiong said. “We discovered that when you force an electron through a chiral structure, which is a type of molecule with a non-reproducible mirror image, it becomes spin polarized and rotates the electron so that it ‘spins’ around. ‘a way that aligns with the chiral structure of other electrons.

“Not only does this process use less energy than conventional spin generation and lose less in the process, but it is also much easier to achieve high-density integration. Our next step is to achieve spin generation spin without magnet using chiral semiconductors made in Biwu’s laboratory instead of the very fragile chiral molecules.

This work was also presented as an invited lecture at the March 2024 meeting of the American Physical Society. Other contributors to this research include scientists from the Chinese Academy of Sciences, the Weizmann Institute of Science, and the University of California, Los Angeles.