Holographic imaging of newly demonstrated Sr doped-BaTiO3 based polar skyrmions heterostructures

Our model engineered Sr doped-BaTiO3 (BST) oxide heterostructure on GdScO3 (001) has been shown to exhibit unusual polar skyrmion states. Such type of polar skyrmions states were recently discovered by PI (S. Das) in PbTiO3/SrTiO3 superlattices [S. Das, et al, Nature 568, 368 (2019)] although for Sr doped-BaTiO3 it remains unexplored, which is highly relevant for high density memory devices and other optimized device applications. Through our meticulous study on both in-plane and out-of-plane amplitude and phase Piezoelectric force microscopy (PFM) images, we confirm the genuine occurrence of polar skyrmions. Here, we propose to study the real-space distribution of skyrmion states as a function of temperature, electric field and thickness of BST layer through coherent lensless imaging techniques able to resolve polar structures down to nanometric scale.