Related papers: Piezoelectricity in hafnia
We demonstrate the formation of epitaxial, ultrathin hafnia (HfO2) on graphene. Monoclinic hafnia (m-HfO2) forms as the end of a series of sequential oxidation reactions. Starting from Hf metal grown epitaxially on graphene, oxidation leads…
The discovery of ferroelectric HfO2 in thin films and more recently in bulk is an important breakthrough because of its silicon-compatibility and unexpectedly persistent polarization at low dimensions, but the origin of its ferroelectricity…
HfO$_{2}$-based ferroelectric thin films are promising for their application in ferroelectric devices. Predicting the ultimate magnitude of polarization and understanding its switching mechanism are critical to realize the optimal…
Recently, based on the phase-field modeling, it was predicted that Hf1-xZrxO2 (HZO) exhibits the morphotropic phase boundary (MPB) in its compositional phase diagram. Here, we investigate the effect of structural changes between tetragonal…
While nature provides a plethora of perovskite materials, only a few exhibits large ferroelectricity and possibly multiferroicity. The majority of perovskite materials have the non-polar CaTiO$_3$(CTO)structure, limiting the scope of their…
HfO$_2$- and ZrO$_2$-based ferroelectric thin films have emerged as promising candidates for the gate oxides of next generation electronic devices. Recent work has experimentally demonstrated that a tetragonal/orthorhombic (t/o-) phase…
While ferroelectric hafnia ($\mathrm{HfO_2}$) has become a technically important material for microelectronics, the physical origin of its ferroelectricity remains poorly understood. The tetragonal $P4_2/nmc$ phase is commonly assigned as…
A non-volatile optical phase shifter is a critical component for enabling large-scale, energy-efficient programmable photonic integrated circuits (PICs) on a silicon (Si) photonics platform. While ferroelectric materials like BaTiO3 offer…
Remarkable exploitation of valence and lattice mismatch in epitaxial ferroelectric heterostructures generates physical effects not classically expected for perovskite oxides, such as 2D electron gas and polar skyrmions. However the…
Antiferroelectricity is a material property characterized by alternating electric dipoles spontaneously ordered in antiparallel directions. Antiferroelectrics are promising for energy storage, solid-state cooling, and memory technologies;…
Hafnium dioxide (HfO2) is a CMOS-compatible ferroelectric showing both 180{\deg} and 90{\deg} switching, yet the microscopic nature of the 90{\deg} pathway remains unresolved. We show that the 90{\deg} rotation pathway, negligible in…
Piezoelectricity is a technologically important property of certain insulators in which mechanical strain induces an electrical polarization. However, the rate at which a piezoelectric response can be established over a macroscopic volume…
The metastable nature of the ferroelectric phase of HfO$_2$ is a significant impediment to its industrial application as a functional ferroelectric material. In fact, no polar phases exist in the bulk phase diagram of HfO$_2$, which shows a…
Different dopants with their specific dopant concentration can be utilized to produce ferroelectric HfO$_2$ thin films. In this work it is explored for the example of Sr in a comprehensive first-principles study. Density functional…
Ferroelectric hafnia is being explored for next generation electronics due to its robust ferroelectricity in nanoscale samples and its compatibility with silicon. However, its ferroelectricity is not understood. Other ferroelectrics usually…
Piezoelectrics play a critical role in various applications. The permanent dipole associated with the molecular cations in organometal-halide perovskites (OMHPs) may lead to spontaneous polarization and thus piezoelectricity. Here, we…
Hafnia ferroelectrics combine technological promise and unprecedented behaviors. Their peculiarity stems from the many active extrinsic mechanisms that contribute to their properties and from a continuously growing number of novel intrinsic…
Metal-organic framework (MOF) UiO-66 nanocrystals were previously believed to be piezo/ferro-electrically inactive because of their centrosymmetric lattice symmetries (Fm-3m (225)) revealed by Powder X-ray diffraction. However, via delicate…
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…
We performed density functional theory (DFT) calculations on epitaxially strained hafnia. We demonstrate the stabilization of the ferroelectric ($Pca2_{1}$) phase from the antiferroelectric ($Pbcn$) in bulk hafnia in the presence of…