相关论文: Theory of Ferroelectric ZrO$_{2}$ Monolayers on Si

A monolayer of ZrO$_{2}$ has recently been grown on the Si(001) surface and shown to have ferroelectric properties, which signifies the realization of the lowest possible thickness in ferroelectric oxides [M. Dogan et al., Nano Lett., 18…

The ground-state structure of monolayers and nanoplatelets of SnS with a thickness from two to five monolayers is calculated from first principles. It is shown that nanoobjects with only odd number of monolayers are ferroelectric. The…

Since the discovery of ferroelectricity in HfO$_2$ thin films, significant research has focused on Zr-doped HfO$_2$ and solid solution (Hf,Zr)O$_2$ thin films. Functional properties can be further tuned via multilayering, however, this…

We report on the crystal structure and ferroelectric properties of epitaxial ZrO$_2$ films ranging from 7 to 42 nm thickness grown on La$_{0.67}$Sr$_{0.33}$MnO$_3$-buffered (110)-oriented SrTiO$_3$ substrate. By employing X-ray diffraction,…

Low dimensional ferroelectrics are highly desired for applications and full of exotic physics. Here a functionalized MXene Hf$_2$CF$_2$ monolayer is theoretically studied, which manifests a nonpolar to polar transition upon moderate biaxial…

Two-dimensional ferroelectric materials are beneficial for power-efficient memory devices and transistor applications. Here, we predict out-of-plane ferroelectricity in a new family of buckled metal oxide (MO; M: Ge, Sn, Pb) monolayers with…

Since the first report of ferroelectricity in nanoscale HfO$_2$-based thin films in 2011, this silicon-compatible binary oxide has quickly garnered intense interest in academia and industry, and continues to do so. Despite its deceivingly…

Zirconia and hafnia based thin films have attracted tremendous attention in the last decade due to their unexpected ferroelectric behavior at the nanoscale, which facilitates the downscaling of ferroelectric devices. The present work…

Density functional calculations are performed to investigate the experimentally-reported field-induced phase transition in thin-film ZrO2 (J. Muller et al., Nano. Lett. 12, 4318). We find a small energy difference of ~ 1 meV/f.u. between…

Flat phonon bands in fluorite ferroelectrics (HfO2 or ZrO2) shrink polar domains laterally to an irreducible half-unit-cell width (0.27 nm) within which the vertical arrangement of dipoles is expected to remain uniform. We report on the…

We present a density functional theory investigation of strained Ca$_{0.5}$Sr$_{0.5}$TiO$_3$. We have determined the structure and polarization for a number of arrangements of Ca and Sr in a 2$\times$2$\times$2 supercell. The a and b…

We simulate from first-principles the energetic, structural, and electronic properties of ferroelectric domains in ultrathin capacitors made of a few unit cells of BaTiO$_3$ between two metallic SrRuO$_3$ electrodes in short circuit. The…

Ferroelectricity is usually found in compound materials composed by different elements. Here, based on first-principles calculations, we reveal the first example of spontaneous electrical polarization and ferroelectricity in stable…

Ferroelectrics are essential in low-dimensional memory devices for multi-bit storage and high-density integration. A polar structure is a necessary premise for ferroelectricity, mainly existing in compounds. However, it is usually rare in…

Twisted heterostructures of two-dimensional crystals offer almost unlimited scope for the design of novel metamaterials. Here we demonstrate a room-temperature ferroelectric semiconductor that is assembled using mono- or few- layer MoS2.…

The structural, thermal, and dielectric properties of the ferroelectric phase of HfO$_2$, ZrO$_2$ and Hf$_{0.5}$ Zr$_{0.5}$ O$_2$ (HZO) are investigated with carefully validated density functional computations. We find, that the free bulk…

The wealth of complex polar topologies recently found in nanoscale ferroelectrics result from a delicate balance between the materials intrinsic tendency to develop a homogeneous polarization and the electric and mechanic boundary…

Two-dimensional electron gas due to semiconductor interfaces can have high mobility and exhibits superconductivity, magnetism, and other exotic properties that are unexpected in constituent bulk materials. We study crystal structures,…

We have studied ferroelectricity and photovoltaic effects in atomic layer deposited (ALD) 40-nm thick SnTiO$_{x}$ films deposited directly onto p-type (001)Si substrate. These films showed well-saturated, square and repeatable hysteresis…

A first-principles-derived approach is used to study structural, piezoelectric and dielectric properties of Pb(Zr_{1-x}Ti_{x})O_{3} (PZT) solid solutions near the morphotropic phase boundary at low temperature. Three ferroelectric phases…