Signatures of enhanced out-of-plane polarization in asymmetric BaTiO superlattices integrated on silicon.

In order to bring the diverse functionalities of transition metal oxides into modern electronics, it is imperative to integrate oxide films with controllable properties onto the silicon platform. Here, we present asymmetric LaMnO/BaTiO/SrTiO superlattices fabricated on silicon with layer thickness control at the unit-cell level. By harnessing the coherent strain between the constituent layers, we overcome the biaxial thermal tension from silicon and stabilize c-axis oriented BaTiO layers with substantially enhanced tetragonality, as revealed by atomically resolved scanning transmission electron microscopy.

Strain-Engineered Metal-to-Insulator Transition and Orbital Polarization in Nickelate Superlattices Integrated on Silicon.

Epitaxial growth of SrTiO (STO) on silicon greatly accelerates the monolithic integration of multifunctional oxides into the mainstream semiconductor electronics. However, oxide superlattices (SLs), the birthplace of many exciting discoveries, remain largely unexplored on silicon. In this work, LaNiO /LaFeO SLs are synthesized on STO-buffered silicon (Si/STO) and STO single-crystal substrates, and their electronic properties are compared using dc transport and X-ray absorption spectroscopy.

An integrated optical modulator operating at cryogenic temperatures.

Photonic integrated circuits (PICs) operating at cryogenic temperatures are fundamental building blocks required to achieve scalable quantum computing and cryogenic computing technologies. Silicon PICs have matured for room-temperature applications, but their cryogenic performance is limited by the absence of efficient low-temperature electro-optic modulation. Here we demonstrate electro-optic switching and modulation from room temperature down to 4 K by using the Pockels effect in integrated barium titanate (BaTiO) devices.

Large Pockels effect in micro- and nanostructured barium titanate integrated on silicon.

The electro-optical Pockels effect is an essential nonlinear effect used in many applications. The ultrafast modulation of the refractive index is, for example, crucial to optical modulators in photonic circuits. Silicon has emerged as a platform for integrating such compact circuits, but a strong Pockels effect is not available on silicon platforms.

Microstructure and ferroelectricity of BaTiO thin films on Si for integrated photonics.

Significant progress has been made in integrating novel materials into silicon photonic structures in order to extend the functionality of photonic circuits. One of these promising optical materials is BaTiO or barium titanate (BTO) that exhibits a very large Pockels coefficient as required for high-speed light modulators. However, all previous demonstrations show a noticable reduction of the Pockels effect in BTO thin films deposited on silicon substrates compared to BTO bulk crystals.