相关论文: Ferroelectricity in $\mathrm{HfO_2}$ from a chemic…
Recent experimental results demonstrate that in thin films ferroelectricity persists down to film thickness of a few unit cells. This finding opens an avenue for novel electronic devices based on ultathin ferroelectrics, but also raises…
Though the electrical responses of the various polymorphs found in ferroelectric polycrystalline thin film HfO$_2$ are now well characterized, little is currently understood of this novel material's grain sub-structure. In particular, the…
The recent discovery of ferroelectric nematic liquid crystalline phases marks a major breakthrough in soft matter research. An intermediate phase, often observed between the nonpolar and the ferroelectric nematic phase, shows a distinct…
The electronic properties of graphene on top of ferroelectric HfO$_2$ substrates in orthorhombic phase with space group Pca2$_1$ are investigated using density functional theory calculations. The space group Pca2$_1$ was recently identified…
Thin films of aluminum hafnium nitride (Al$_{1-x}$Hf$_{x}$N) were synthesized via reactive magnetron sputtering for Hf contents up to $x$ = 0.13. X-ray diffraction showed a single $c$-axis oriented wurtzite phase for all films. Hard X-ray…
Doping a parent antiferromagnetic Mott insulator in cuprates leads to short-range electronic correlations and eventually to high-Tc superconductivity. However, the nature of charge correlations in the lightly doped cuprates remains unclear.…
Hybrid improper ferroelectrics (HIFs) have been intensely studied over the last few years to gain understanding of their temperature induced phase transitions and ferroelectric switching pathways. Here we report a switching from first- to…
Oxyhydroxide minerals like FeOOH have been a research focus in geology for studying the Earth interior, and also in chemistry for studying oxygen electrocatalysis activity. In this paper we provide first-principles evidence of a new class…
Since there is both strong electron-phonon coupling during a ferroelectric/FE transition and superconducting/SC transition, it has been an important topic to explore superconductivity from the FE instability. Sn$_2$P$_2$Se$_6$ arouses broad…
We have performed dielectric measurements and neutron diffraction experiments on the double perovskite In2NiMnO6. A ferroelectric polarization, P ~ 30 {\mu}C/m2, is observed in a polycrystalline sample below TN = 26 K where a magnetic phase…
Electric polarization typically originates from non-centrosymmetric charge distributions in compounds. In elemental crystalline materials, chemical bonds between atoms of the same element favor symmetrically distributed electron charges and…
Within the broad class of multiferroics (compounds showing a coexistence of magnetism and ferroelectricity), we focus on the subclass of "improper electronic ferroelectrics", i.e. correlated materials where electronic degrees of freedom…
Atomic-scale ferroelectric thin films hold great promise for high-density, low-power applications but face stability and voltage scaling challenges at extreme thinness. Here, we demonstrate ferroelectricity in single-crystalline…
The structure of ABO3 perovskites is dominated by two types of unstable modes, namely, the oxygen octahedral rotation (AFD) and ferroelectric (FE) mode. It is generally believed that such AFD and FE modes tend to compete and suppress each…
We present a first-principles investigation of ferroelectricity in layered perovskite oxide La2Ti2O7 (LTO), one of the compounds with highest Curie temperature known (1770 K). Our calculations reveal that LTO's ferroelectric transition…
The wake-up phenomenon widely exists in hafnia-based ferroelectric capacitors, which causes device parameter variation over time. Crystallization at higher temperatures have been reported to be effective in eliminating wake-up, but high…
HfO2-based ferroelectric films have attracted considerable attention as their nanoscale ferroelectricity and compatibility with cmos technology, fulfilling demands of emerging memory technologies. However, as films scale down,…
We investigate the effect of polar Sr-O vacancy pairs on the electric polarization of SrMnO$_3$ (SMO) thin films using density functional theory (DFT) calculations. This is motivated by indications that ferroelectricity in complex oxides…
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…
A ferroelectric material often exhibits a soft transvers optical (TO) phonon mode which governs it phase transition. Charge coupling to this ferroelectric soft mode may further mediate emergent physical properties, including…