Nanoscale self-organization and metastable non-thermal metallicity in Mott insulators

Andrea Ronchi , Paolo Franceschini , Andrea de Poli , Pía Homm , Ann Fitzpatrick , Francesco Maccherozzi , Gabriele Ferrini , Francesco Banfi , Sarnjeet Dhesi , Mariela Menghini , Michele Fabrizio , Jean-Pierre Locquet , Claudio Giannetti

Mott transitions in real materials are first order and almost always associated with lattice distortions, both features promoting the emergence of nanotextured phases. This nanoscale self-organization creates spatially inhomogeneous regions, which can host and protect transient non-thermal electronic and lattice states triggered by light excitation. Here, we combine time-resolved X-ray microscopy with a Landau-Ginzburg functional approach for calculating the strain and electronic real-space configurations. We investigate V 2 O 3 , the archetypal Mott insulator in which nanoscale self-organization already exists in the low-temperature monoclinic phase and strongly affects the transition towards the high-temperature corundum metallic phase. Our joint experimental-theoretical approach uncovers a remarkable out-of-equilibrium phenomenon: the photo-induced stabilisation of the long sought monoclinic metal phase, which is absent at equilibrium and in homogeneous materials, but emerges as a metastable state solely when light excitation is combined with the underlying nanotexture of the monoclinic lattice.

Domaines: Sciences de l'ingénieur [physics]; Chimie; Physique [physics]

Andrea Ronchi, Paolo Franceschini, Andrea de Poli, Pía Homm, Ann Fitzpatrick, et al.. Nanoscale self-organization and metastable non-thermal metallicity in Mott insulators. Nature Communications, 2022, 13 (1), pp.3730. ⟨10.1038/s41467-022-31298-0⟩. ⟨hal-03725657⟩