PRIN PNRR 2022 P2022KSTSR - Opto-mechanical effects in spin-defects for quantum technologies - Finanziamento dell’Unione Europea – NextGenerationEU – missione 4, componente 2, investimento 1.1. - CUP: D53D23019370001

The goal of this joint theoretical-experimental program is to study property-function relationships useful to design and control solid-state spin-defects for quantum information science. The program addresses a grand challenge: the design of materials that can host quantum states that are both robust and easily controllable with light. Electrons bound by a point-defect to a region on the order of a single lattice constant can be regarded as analogues of atomic systems in an effective vacuum, with spin and optical properties that are determined by the interplay between the defect and its host local environment. So far, the NV center in diamond has represented the most studied prototypical example, with proven room temperature operability. Several candidate defects and host materials are under scrutiny in order to realize an optical interface in the telecom range, to be embedded in materials that possess a scalable fabrication process and exhibit long coherence times for improved quantum functionality. Key science questions that will guide this research include: How does the local environment surrounding the defect site influence its spin-polarization? How can light activated processes be simulated and characterized accurately in complex heterogeneous materials? What factors can be controlled in order to generate good quantum functionalities? The proposed research will leverage computational and experimental resources in several previously unexplored directions: we propose to investigate spin-strain and spin-phonon processes to enhance the opto-mechanical interface of spin-defects for quantum communication and sensing. The effect of strain on the spin-opto-electronic properties of point-defects will be quantified theoretically using first principles simulations based on the density functional theory and Green’s function embedding methods, and compared to experimental measurements that use confocal microscopy mapping and local strain engineering. We will study color centers in strained diamond and SiC for sensing pressure and magnetic fields. We will theoretically identify stable spin-defects in technologically relevant materials (Si, III-nitrides, oxide ceramics) with long decoherence times, focusing on strain-induced processes (piezoelectricity, hetero-epitaxy) as means to tailor the optical interface of the spin-defect. Finally, we will study light-induced local strain and electric field in pairs of interacting point-defects as a new avenue for controlling their spin-polarization. To achieve the ambitious goals set forth in this program, the research plan will combine expertise in computational materials science (Govoni, UniMoRe) and experimental characterization of defects in materials (Forneris, UniTo). This program targets research that is focused on strengthening the EU capacities in key parts of materials discovery and quantum connectivity (Cluster 4: Digital, Industry and Space).