Engineering quantum electronic materials by phonon-polariton metamaterials

点击翻译按钮获取中文摘要

Quantum mechanics describes electrons in materials as both particles and wavefunctions. In “quantum materials” the entangled electronic wavefunctions exhibit properties that differ from conventional metals, semiconductors or insulators. Controlling these properties not only advances our understanding of the fundamental interactions among electrons, but also promises new devices for next-generation information technology. Light contains oscillating electric field, so at the right frequency light can simultaneously strongly couple with motions of both electrons and atoms. These coupled electrons and atoms may enter entirely different states from those in existing materials. This project designs hybrid materials with both enhanced light-matter interactions and quantum correlations. The characterization of these materials dynamically engineered by light potentially provides insights into emergent phenomena like unconventional superconductivity. Besides scientific impact, this program trains the next-generation STEM workforce through research opportunities for community college students. It will also raise awareness of quantum technology to a broader audience by a new course in quantum materials engineering.Non-equilibrium open systems such as Floquet states, present in time-periodic fields, emerge as new platforms to create quantum materials on demand. The dynamic nature of such systems makes it possible to override stability constraints and induce new electronic structures in old materials. Experimental investigation of optically driven states at the presence of electronic correlation is particularly important due to the rich physics and the difficulty in theoretical treatment. However, studying coherent dynamics in solids faces practical challenges such as interband transition and lattice dissipation. This project seeks to overcome some of the challenges by coupling materials supporting phonon-polaritons and materials hosting gapped interacting electrons. Exciting the phonon-polariton with resonant pulsed light provides the necessary strong field and fast coherent evolution that outpaces thermalization. Using metamaterials consisting of micro-resonators, the light intensity can exceed those commonly achievable by table-top sources. Meanwhile, the frequency of phonon-polaritons in the metamaterial is chosen to reduce both the multi-photon transition and the field-induced ionization. The transient changes of electronic energy levels, transport properties and dissipation dynamics are subsequently probed by time-resolved spectroscopy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.