IQUIST Seminar Series: Daniel Shoemaker, University of Illinois, Urbana-Champaign

Описание: "Engineering atomic networks in crystals"
Abstract: Quantum applications demand excitations with high fidelity and known connectivity. In the solid state, for ions in crystalline materials, the energy landscape that determines connectivity (the network of chemical bonds) has a much larger scale than the modern applications (optical, microwave, etc.) that probe them. One benefit is that this energy scale should self-organize the materials into uniform bonding environments. However, nature’s propensity for order comes with a cost: it can be very challenging to design atomic networks from scratch, and materials that grow with imperfections have those defects locked in; they cannot be corrected in post-processing. I will explain how we use chemical rules and bonding networks to identify promising uninvestigated or undiscovered materials. Of current interest are compounds containing rare earth ions for quantum memory, charge density waves materials that host exotic excitations, and new or high-quality layered van der Waals materials. Even with promising materials in mind, the task of crystal growth is still daunting. Due to the required millimeter dimensions, they must be grown from solutions, fluxes, or vapors. This process is often hard to observe and highly kinetically dependent, so in situ techniques can be especially valuable. With a clearer view of how materials form, we can critically evaluate computational predictions (ab initio or machine-learned methods) and explore novel reactions to target new phases.