Ferromagnetic stability optimization via oxygen-vacancy control in single-atom Co/TiO nanostructures.

Oxygen vacancies and their correlation with the nanomagnetism and electronic structure are crucial for applications in dilute magnetic semiconductors design applications. Here, we report on cobalt single atom-incorporated titanium dioxide (TiO) monodispersed nanoparticles synthesized using a thermodynamic redistribution strategy. Using advanced synchrotron-based X-ray techniques and simulations, we find trivalent titanium is absent, indicating trivalent cations do not influence ferromagnetic (FM) stability.

Micrometre-scale single-crystalline borophene on a square-lattice Cu(100) surface.

Borophene, a crystalline monolayer boron sheet, has been predicted to adopt a variety of structures-owing to its high polymorphism-that may possess physical properties that could serve in flexible electronics, energy storage and catalysis. Several borophene polymorphs have been synthesized on noble metal surfaces but for device fabrication larger single-crystal domains are typically needed with, ideally, weak borophene-substrate interactions. Here we report the synthesis of borophene on a square-lattice Cu(100) surface and show that incommensurate coordination reduces the borophene-substrate interactions and also leads to a borophene polymorph different from those previous reported.

Designing and controlling the properties of transition metal oxide quantum materials.

This Perspective addresses the design, creation, characterization and control of synthetic quantum materials with strong electronic correlations. We show how emerging synergies between theoretical/computational approaches and materials design/experimental probes are driving recent advances in the discovery, understanding and control of new electronic behaviour in materials systems with interesting and potentially technologically important properties. The focus here is on transition metal oxides, where electronic correlations lead to a myriad of functional properties including superconductivity, magnetism, Mott transitions, multiferroicity and emergent behaviour at picoscale-designed interfaces.

Tuning two-dimensional phase formation through epitaxial strain and growth conditions: silica and silicate on NiPd(111) alloy substrates.

Two-dimensional (2D) materials can have multiple phases close in energy but with distinct properties, with the phases that form during growth dependent on experimental conditions and the growth substrate. Here, the competition between 2D van der Waals (VDW) silica and 2D Ni silicate phases on NiPd(111) alloy substrates was systematically investigated experimentally as a function of Si surface coverage, annealing time and temperature, O partial pressure, and substrate composition and the results were compared with thermodynamic predictions based on density functional theory (DFT) calculations and thermochemical data for O. Experimentally, 2D Ni silicate was exclusively observed at higher O pressures (∼10 Torr), higher annealing temperatures (1000 K), and more prolonged annealing (10 min) if the substrate contained any Ni and for initial Si coverages up to 2 monolayers.

Strong Orbital Polarization in a Cobaltate-Titanate Oxide Heterostructure.

Through a combination of experimental measurements and theoretical modeling, we describe a strongly orbital-polarized insulating ground state in an (LaTiO_{3})_{2}/(LaCoO_{3})_{2} oxide heterostructure. X-ray absorption spectra and ab initio calculations show that an electron is transferred from the titanate to the cobaltate layers. The charge transfer, accompanied by a large octahedral distortion, induces a substantial orbital polarization in the cobaltate layer of a size unattainable via epitaxial strain alone.