Mott resistive switching initiated by topological defects.

Avalanche resistive switching is the fundamental process that triggers the sudden change of the electrical properties in solid-state devices under the action of intense electric fields. Despite its relevance for information processing, ultrafast electronics, neuromorphic devices, resistive memories and brain-inspired computation, the nature of the local stochastic fluctuations that drive the formation of metallic regions within the insulating state has remained hidden. Here, using operando X-ray nano-imaging, we have captured the origin of resistive switching in a VO-based device under working conditions.

Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial VO Films.

Dimensional confinement has shown to be an effective strategy to tune competing degrees of freedom in complex oxides. Here, we achieved atomic layered growth of trigonal vanadium sesquioxide (VO) by means of oxygen-assisted molecular beam epitaxy. This led to a series of high-quality epitaxial ultrathin VO films down to unit cell thickness, enabling the study of the intrinsic electron correlations upon confinement.

Efficient Direct Band-Gap Transition in Germanium by Three-Dimensional Strain.

Complementary to the development of highly three-dimensional (3D) integrated circuits in the continuation of Moore's law, there has been a growing interest in new 3D deformation strategies to improve the device performance. To continue this search for new 3D deformation techniques, it is essential to explore beforehand, using computational predictive methods, which strain tensor leads to the desired properties. In this work, we study germanium (Ge) under an isotropic 3D strain on the basis of first-principles methods.