Collaborative Research: DMREF: NSF-DFG: Atoms-to-Device Closed-Loop Predictive Design of Electro-Optic Materials for Quantum Photonic Circuits

• Applicant: Professor Dr. Roman Engel-Herbert
• Subject Area: Synthesis and Properties of Functional Materials ; Computer-Aided Design of Materials and Simulation of Materials Behaviour from Atomic to Microscopic Scale ; Experimental Condensed Matter Physics
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 565900917

A central goal of Materials Genomics is to predict superior intrinsic material properties on the atomic scale and translate them to superior effective properties in technology we can touch and hold. However, most such material discoveries are lost in translation due to the “mesoscale cliff,” where microstructures on nm-100’s 𝜇m scale dominate device performance. This proposal focuses on addressing such a materials challenge, namely, to develop a fundamental knowledge base to deploy the next generation of cryogenic electro-optic (EO) materials integrated on Si for chip-scale quantum integrated circuits. The electro-optic (EO) effect describes a material’s optical refractive index change upon the application of an electric field; it powers our internet today. They are also fundamental building blocks for the emerging scalable optical quantum computing hardware, on-chip trapped ion quantum computing schemes and developments in low temperature science. With these, new materials’ challenges arise: EO modulators must now respond fast (5- 100 GHz), be operated at cryogenic temperatures (10-20 mK) with low energy budget (< pJ/bit) and must be integrated directly on silicon (Si). This requires materials with cryogenic EO coefficients >1000 pm/V, which is >30× of the current industry standard. In addition, they require large index and low optical loss at the telecom wavelength with low microwave dielectric constant and loss for low power, low loss operation. Complex oxides appear to be the most promising, but a lack of fundamental understanding on the mesoscale is undermining this effort with severely degraded performances in going from atoms to devices. Our DMREF team is poised to make a big impact here with a new theory approach informing experimental breakthroughs. Our team proposes an Atoms-to-Devices (A2D) design approach that is firmly rooted in the materials genome framework. It has three interlocking gears (Thrusts): (1) Density Functional Theory informed Thermodynamic Theory of Electro-Optics, (2) Thermodynamics integrated Phase-Field Simulations, and (3) Phase-Field-integrated Electrodynamics Simulation package. We will (1) build a foundational bridge between the atomic scale and the mesoscale using a modern thermodynamic theory of electro-optics to predict and validate new materials with superior intrinsic EO properties, (2) experimentally validate complex mesoscale microstructures and their effective EO properties, and (3) integrate phase-field modeling and electrodynamics simulations to design a digital twin of the physical modulator devices and their performances. A robust experimental testing and validation is built into each Thrust involving crystal and thin film synthesis, integration on Si, and characterization of structure and properties from the atomic to the device level. With our closed-loop MGI approach, we are confident of making a transformative impact on this critical materials challenge facing the emerging quantum technologies.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partners: Professor Long-Qing Chen; Professor Venkatraman Gopalan; Professor Joshua Young, Ph.D.