arXiv subjects

Johanna van Gent González

Publications and source records attributed to Johanna van Gent González.

2 recordsLinked to original sources

arXiv2026

Domain-wall-to-domain interconversion in a polar conducting oxide

Domain walls in ferroic crystals are topological defects with a symmetry distinct from the domain interior, allowing them to display functionalities that are otherwise forbidden in the host material. Despite their unique properties, domain walls are strictly confined to two-dimensional interfaces, which hinders unveiling their true nature and limits their applicability. Here, we demonstrate reversible dimensionality control by expanding nanoscale domain walls into three-dimensional functional regions in polar epitaxial tungsten trioxide ($\text{WO}_3$). This domain-wall-to-domain interconversion is enabled by the conducting, non-polar domain walls adopting the parent-phase structure. An alternating electric field applied through a scanning probe tip induces localized heating, which expands this domain-wall phase into the adjacent polar domains. This approach enables reversible spatial control to switch between mutually exclusive properties of domains (polarity) and domain walls (conductivity), offering a new paradigm for reconfigurable oxide electronics.

cond-mat.mtrl-sci↗

arXiv2025

Polarity and anti-distortive polarons in WO3 through epitaxial shear strain

Bestowing CMOS-compatible binary oxides with additional functionalities is a powerful strategy toward the realization of oxide electronics. Ideal candidates are thin films which display a strong sensitivity to strain, chemical doping or nanoscale confinement. Among these, crystalline tungsten trioxide WO3 exhibits exceptional structural flexibility, enabling a wide range of functionalities. Here, we reveal the emergence of a previously unreported polar phase in epitaxial WO3 thin films. We accomplish this by imposing epitaxial shear strain, which stabilizes a low-symmetry triclinic structure that persists up to large film thicknesses and elevated temperatures. At the atomic scale, a change in the oxygen octahedral tilt pattern facilitates this symmetry lowering into a polar phase, which manifests as a periodic in-plane polarized stripe domain configuration with needle-like bifurcations at the microscale. The stripe domain walls further exhibit a strongly enhanced electrical conductivity in conjunction with a pronounced reduction of a distortive structural mode, providing the first experimental evidence for the formation of anti-distortive polarons recently predicted in WO3.

cond-mat.mtrl-sci↗