"U.S. Innovates with Graphene and Quantum Technology to Create Advanced Chip Inductors"

Researchers in the United States have achieved a significant reduction in the size of chip inductors by integrating a concept known as "kinetic inductance" alongside traditional magnetic induction methods. This innovative approach has led to a decrease in the dimensions of inductors operating in the frequency range of 10-50 GHz by approximately one-third.

The research team from the University of California, Santa Barbara, posits that kinetic inductance arises from the fundamental quantum behavior of charge currents, which resist alterations in their flow direction due to variations in the electric field. This kinetic inductance operates in conjunction with the conventional magnetic inductance found in standard inductors.

Typically, metals commonly used in inductors exhibit minimal kinetic inductance. Professor Kaustav Banerjee, who leads the project, noted that while the theory of dynamic inductance has been recognized in condensed matter physics for some time, its application in inductors has been limited due to the negligible dynamic inductance in conventional metallic conductors.

To overcome this limitation, the research team developed a novel material featuring enhanced kinetic inductance: a multi-layer graphene structure with bromine atoms inserted between its layers. Single-layer graphene is characterized by a linear electronic band structure and a relatively long momentum relaxation time (MRT) of several picoseconds, which is significantly longer than that of traditional metal conductors like copper, which ranges from 1 to 10 femtoseconds. However, single-layer graphene's resistance to inductance is excessively high.

While multi-layer graphene offers a partial remedy by reducing resistance, its momentum relaxation time is still inadequate due to the coupling between layers. The researchers found that chemically inserting bromine atoms between the graphene layers effectively separates them, thereby enhancing kinetic inductance by extending the MRT and further minimizing resistance.

The resulting material is then formed into a spiral inductor. Scientist Junkai Jiang emphasized that by optimizing the embedding process, there is considerable potential to further increase the inductance density.

This groundbreaking research has been published in a prominent journal, highlighting the development of plate-embedded graphene inductors designed for next-generation radio frequency electronics. The Nanoelectronics Research Laboratory at UCSB is collaborating with institutions such as the Shiba Institute of Technology in Japan and Shanghai Jiaotong University in China to advance this innovative technology.