Periodic Reporting for period 1 - Twist-TOC (Probing emergent phenomena in twisted WSe2 using THz-on-Chip spectroscopy)
Période du rapport: 2023-09-01 au 2025-08-31
The aim of this project was to investigate low-energy phases in gate-tunable van der Waals heterostructures using on-chip terahertz (THz) spectroscopy, with particular relevance to twisted WSe2. Achieving this objective required establishing, validating and quantitatively understanding the experimental platform necessary to apply this technique reliably to complex Moiré materials.
Accordingly, a starting point for this project focused on benchmark measurements on monolayer graphene, which served as a previously well characterized test sample. Early measurements revealed previously unanticipated finite-size and dielectric self-cavity effects inherent to on-chip THz devices, demonstrating that platform-specific electrodynamic effects play a critical role in the measured low-energy response and must be accounted for before intrinsic material properties can be reliably determined.
To these ends, over 42 THz devices were measured, including 15 THz circuitry optimization devices, 16 bare graphite cavities, and 6 gate-tunable graphene devices. These experimental measurements were combined with numerical simulations to characterize the optical responses of these samples and develop an analytical framework for both understanding their cavity conductivity, which contains information on the finite size and dielectric environment of devices, as well as their intrinsic 2D conductivity of the material. This approach enables these effects to be quantitatively disentangled from the intrinsic response of a material.
The results of this work were published in Nature Physics, Optical Materials Express, and APL Photonics. Further manuscripts related to this project are under review in Nature Communications and Nature Materials. In addition, the results were shared at conferences and seminars across Europe and the US with the acknowledgment of funding always shared on slides and posters.
To these ends, over 42 THz devices were measured, including 15 THz circuitry optimization devices, 16 bare graphite cavities, and 6 gate-tunable graphene devices. These experimental measurements were combined with numerical simulations to characterize the optical responses of these samples and develop an analytical framework for both understanding their cavity conductivity, which contains information on the finite size and dielectric environment of devices, as well as their intrinsic 2D conductivity of the material. This approach enables these effects to be quantitatively disentangled from the intrinsic response of a material.
The results of this work were published in Nature Physics, Optical Materials Express, and APL Photonics. Further manuscripts related to this project are under review in Nature Communications and Nature Materials. In addition, the results were shared at conferences and seminars across Europe and the US with the acknowledgment of funding always shared on slides and posters.
The results of this project demonstrated a novel method for manipulating quantum materials properties, naturally bringing together the fields of cavity quantum materials and vdW heterostructures. The exploitation of these findings has begun in a number of additional research projects that are just beginning to demonstrate preliminary results. In addition, this research vision will also be shared to ensure further uptake in a review article that will soon be submitted, and which introduces the use of plasmonic cavities in manipulating ground state quantum phases. Future work will take place in research laboratories, but the ideas and design principles that can be developed due to this new capacity, could in the future be used to engineer and improve realistic devices for applications.