The IMPULSE project (In situ MaPping insulator-to-metal transitions by Ultra-high resolution electron SpEctromicroscopy) will develop the characterization tools capable of mapping at sub-nanometer scale the insulating/metallic (I/M) nanodomains induced by insulator-to-metal transition (IMT). In situ ultra-high resolution electron spectromicroscopy (UHR-STEM/EELS) experiments will develop to probe and map the whole relevant electronic excitations (from IR to soft X-ray) at the sub-nanometer scale in Mott insulators and strongly electron correlated systems while monitoring their electric-field-activated and T-induced IMTs, respectively. These general objectives will be achieved through the implementation of short electric pulse generation coupled to the biasing system or using low(controlled)-T stage holders. Beyond that, instrumental advances will be developed on the original data acquisition, detection and post-processing to achieve atomic resolution hyperspectral spectroscopic mapping under in operando conditions. Nanostructured V2O3 with or without Cr substitution: (V1-xCrx)2O3 have been selected as model systems to (i) perform the initial proof-of-principles in situ UHR-STEM/EELS experiments and (ii) explore the local correlation between the structural evolution and the emergence of the metallic state. It will improve our understanding of strongly correlated systems by (i) mapping directly the coexisting I/M domains for the first time at sub-nm scale, (ii) correlating this nanoscale electronic phase separation with their atomic and electronic structures under the realistic operating conditions and (iii) relating these findings to their macroscopic physical properties.

Project coordinator

Laura Bocher

ANR funding

271 k€

Beginning and duration of the scientific project

October 2019 (extended) – 42 months