Stony Brook Researchers Redefine Capacitor Behavior at the Nanoscale

Stony Brook University researchers led a new study published in Physical Review Letters that overturns long-standing assumptions about how capacitors operate when engineered at the nanoscale, offering a clearer scientific foundation for future nanoscale electronic devices.

Capacitors—core components of modern electronics—store electrical charge between metallic electrodes separated by a dielectric material. While their performance is well understood at macroscopic scales, conventional models break down at the nanoscale, where the material properties assumed in standard equations are no longer well defined. These discrepancies pose significant challenges for interpreting the dielectric response of ultrathin materials and for designing reliable nanocapacitors.

To address this problem, the SBU team developed a quantum-mechanical framework that unambiguously separates the contributions of the electrodes and the dielectric. The new protocol establishes fundamental limits on how small a capacitor can be made and provides a reliable approach for evaluating the intrinsic behavior of nanoscale insulating materials.

Demonstrating the method on ultrathin ice, the researchers found that its electronic response to electric fields is essentially indistinguishable from that of bulk ice, despite extreme confinement. The result resolves discrepancies between theoretical predictions and experimental measurements of ice films only a few molecules thick.

“This work offers a pathway to accurately characterize ultrathin dielectric materials using first-principles calculations,” said Ph.D. candidate Anthony Mannino, the study’s lead author. “With a clearer understanding of nanoscale dielectric behavior, we can improve device design and better interpret experimental data.”

The study was led by Mannino, together with fellow Ph.D. candidate Kedarsh Kaushik and visiting student Graciele M. Arvelos, under the direction of Professor Marivi Fernández-Serra at Stony Brook University’s Institute for Advanced Computational Science (IACS), where Mannino is a recipient of the IACS Graduate Fellowship.

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