Speaker
Description
Spatially resolved surface probes have recently revealed rich electronic textures at the nanoscale and mesoscale in many quantum materials. Rather than transitioning from insulator to metal all at once, VO2 forms an intricate network of metallic puddles that extend like filigree over a wide range of temperatures. We developed a convolutional neural network to harvest information from both optical microscope and scanning near field optical images of the metallic filigree. The neural network was able to identify the factors that cause electrons to clump during the transition, such as interactions with defects in the material and the strength of the electron-electron interactions. This reveals that the intricate patterns share universal features with domain structures in magnets, stripe orientation fractals in superconductors, and antiferromagnetic domains in rare earth nickelates, pointing to a universal origin of electron clumping in quantum materials. This identification opens the door to using hysteresis effects to sculpt the filigree, in order to improve the function of VO2 in novel electronic applications such as neuromorphic devices. [Phys. Rev. B 107, 205121 (2023); Nature Commun. 14, 2622 (2023); Nature Commun., 10, 4568 (2019)]
