Symmetry Engineering of Epitaxial HfZrO Ultrathin Films.

Robust ferroelectricity in HfO-based ultrathin films has the potential to revolutionize nonvolatile memory applications in nanoscale electronic devices because of their compatibility with the existing Si technology. However, to fully exploit the potential of ferroelectric HfO-based thin films, it is crucial to develop strategies for the controlled stabilization of various HfO-based polymorphs in nanoscale heterostructures. This study demonstrates how substrate-orientation-induced anisotropic strain can engineer the crystal symmetry, structural domain morphology, and growth orientation of ultrathin HfZrO (HZO) films.

Hemispherically asymmetric Hadley cell response to CO removal.

A poleward shift of the Hadley cell (HC) edge in a warming climate, which contributes to the expansion of drought-prone subtropical regions, has been widely documented. The question addressed here is whether this shift is reversible with CO removal. By conducting large-ensemble experiments where CO concentrations are systematically increased and then decreased to the present-day level, we show that the poleward-shifted HC edge in a warming climate does not return to its present-day state when CO concentrations are reduced.