Greene Dissertation Award Winner: Negative Capacitance Electronics: Manipulating Ferroelectricity in Atomically Thin Simple Materials

The explosion in energy consumption from microelectronics is projected to exceed 20% of worldwide electricity production by 2030 and is continuing to exponentially rise, which calls for fundamental breakthroughs in information processing and on-chip energy technologies. In this talk, I will introduce electronic metamaterials as a new atomic scale platform towards this goal of energy-efficient and energy-autonomous electronics, in which negative capacitance phenomena lead to unprecedented charge responses beyond what is possible in traditional materials. All discoveries will be demonstrated in the model system of HfO₂-ZrO₂ thin films on Si, the conventional dielectrics in today’s microelectronics, to establish atomic-scale confinement of simple 3D materials – down to its unit cell thickness – as a powerful strategy to unlock previously hidden electronic phenomena. I will primarily present the microscopic origins underlying negative capacitance behavior in ultrathin HfO₂-ZrO₂ films, namely frustrated ferroelectric-antiferroelectric order and negative piezoelectricity, and how manipulating symmetry in atomically thin heterostructures can stabilize such ground states. In closing, I will briefly establish negative capacitance effects in ultrathin HfO₂-ZrO₂ films as a new paradigm for (i) ultra-low power computing beyond conventional high permittivity dielectric transistors and (ii) ultra-fast energy storage beyond conventional electrochemical supercapacitors.