Related papers: Stabilizing polar phases in binary metal oxides by…
The electronic structure of Li-doped Ni$_{1-x}$Fe$_x$O has been investigated using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). The Ni $2p$ core-level PES and XAS spectra were not changed by Li doping. In…
Hafnia (HfO2) is a silicon-compatible dielectric material, yet stabilizing its desired but metastable ferroelectric phase remains challenging. Phase stability predictions by density functional theory (DFT) have provided crucial guidance,…
A comparative theoretical study is presented for the rhombohedral R3 and R3m phase HfO2, of two possible forms in its heavily Zr-doped ferroelectric thin films found recently in experiments. Their structural stability and polarization under…
Nearly all ultrawide-bandgap oxides are affected by hole localization that limits $p$-type conductivity and thus potential applications for these materials. Highly localized holes, also known as hole polarons, trap in the vicinity of…
The doping of charge carriers into the CuO2 planes of copper oxide Mott insulators causes a gradual destruction of antiferromagnetism and the emergence of high-temperature superconductivity. Optimal superconductivity is achieved at a doping…
Intertwined ionic conduction and ferroelectric (FE) switching in HfO2 lead to extensive focuses. To describe its fundamental phenomena, we present a free-energy model describing the potential of ferroelectrics with successive FE switching…
In this manuscript, recent theoretical investigations by the authors in the area of oxide multilayers are briefly reviewed. The calculations were carried out using model Hamiltonians and a variety of non-perturbative techniques. Moreover,…
In this work we study the stabilization of the orthorhombic phases in small Hf0.5Zr0.5O2 nanoparticles (average size ~ 7 nm) annealed under different oxygen partial pressures. Concentration of the oxygen vacancies, which is determined by…
In this study, we investigate the formation of electron and hole small polarons in the prototypical ferroelectric material BaTiO3, with a focus on their interaction with ferroelectric distortive fields. To accurately describe the…
Recently an air-stable layered semiconductor Bi2O2Se was discovered to exhibit an ultrahigh mobility in transistors fabricated with its thin layers. In this work, we explored the mechanism that induces the high mobility and distinguishes…
Bismuth titanate, Bi$_4$Ti$_3$O$_{12}$ (BiT), is a complex layered ferroelectric material that is composed of three perovskite-like units and one fluorite-like unit stacked alternatively along the $c$-direction. The ground state crystal…
The coupling of ferroelectricity (FE) and superconductivity (SC) becomes the frontier of condensed matter research recently especially in the realm of two-dimensional (2D) materials. Identifying a general strategy to realize coexistence of…
Bismuth perovskites ABiO$_3$ (A = Sr, Ba) host a variety of peculiar phenomena including bond-disproportionated insulating phases and high-temperature superconductivity upon hole doping. While the mechanisms underlying these phenomena are…
The direction of ferroelectric polarization is prescribed by the symmetry of the crystal structure. Therefore, rotation of the polarization direction is largely limited, despite the opportunity it offers in understanding important…
Ferroelectricity, especially in hafnia-based thin films at nanosizes, has been rejuvenated in the fields of low-power, nonvolatile and Si-compatible modern memory and logic applications. Despite tremendous efforts to explore the formation…
Transition metal oxide perovskites are an ideal platform for exploring the interplay between spin, orbital, charge and lattice degrees of freedom. Among them, \ce{LaVO3} has been extensively studied in heterostructures and superlattices,…
Charge doping is an effective way to induce metal-insulate transition (MIT) in correlated materials for many important utilizations, which is however practically limited by problem of low stability. In this study, we have achieved…
The critical impact of epitaxial stress on the stabilization of the ferroelectric orthorhombic phase of hafnia is proved. Epitaxial bilayers of Hf0.5Zr0.5O2 and La0.67Sr0.33MnO3 electrodes were grown on a set of single crystalline oxide…
Fluorite-type $\mathrm{HfO_2}$-based ferroelectric (FE) oxides have rekindled interest in FE memories due to their compatibility with silicon processing and potential for high-density integration. The polarization characteristics of FE…
Atomic force microscopy and second-harmonic generation data show that boron doping enhances the rate of oxidation of H-terminated silicon. Holes cause a greater increase in the reactivity of the Si-H up bonds than that of the Si-Si back…