Related papers: Negative piezoelectricity in quasi-two/one-dimensi…
Two-dimensional (2D) van der Waals (vdW) materials and their bilayers have stimulated enormous interests in fundamental researches and technological applications. Recently, a group of 2D vdW III2-VI3 materials with out-of-plane…
Vertical ferroelectricity where a net dipole moment appears as a result of in-plane ionic displacements has gained enormous attention following its discovery in transition metal dichalcogenides. Based on first-principles calculations, we…
Van der Waals (vdW) layered materials have rather weaker interlayer bonding than the intra-layer bonding, therefore the exfoliation along the stacking direction enables the achievement of monolayer or few layers vdW materials with emerging…
A series of oxytetrahalides WO$X_4$ ($X$: a halogen element) that form quasi-one-dimensional chains is investigated using first-principles calculations. The crystal structures, electronic structures, as well as ferroelectric and…
Proximity ferroelectricity is a novel paradigm for inducing ferroelectricity, where a non-ferroelectric polar material, which is unswitchable with an external field below the dielectric breakdown field, becomes a practically switchable…
Multifunctional capability, flexible design, rugged lightweight construction, and self-powered operation are desired attributes for electronics that directly interface with the human body or with advanced robotic systems. For these and…
The properties of dielectric and piezoelectric oxides are determined by their processing history, crystal structure, chemical composition, microstructure, dopants (or defect) distribution, and defect kinetics. These materials are essential…
The polarization and piezoelectric response of the BiTe$X$ ($X$=Cl, Br, and I) layered tellurohalides are computed from first principles. The results confirm a mixed ionic-covalent character of the bonding, and demonstrate that the internal…
While piezoelectrics and ferroelectrics are playing a key role in many everyday applications, there are still a number of open questions related to the physics of those materials. In order to foster the understanding of piezoelectrics and…
Using first-principles density functional theory, we study piezoelectricity in short-period superlattices made with combination of ferroelectric and paraelectric components and exhibiting polar discontinuities. We show that piezoelectric…
Interfacial ferroelectricity emerges in heterostructures consisting of nonpolar van der Waals (vdW) layers, greatly expanding the scope of two dimensional ferroelectrics. In particular, the unconventional moire ferroelectricity observed in…
In conventional ferroelectrics the electric dipoles are generated by off-center displacements of ions. In recent years, a new type of so-called electronic ferroelectrics has attracted great attention, where the polarization is driven by…
Understanding the effect of electric fields on the physical and chemical properties of two-dimensional (2D) nanostructures is instrumental in the design of novel electronic and optoelectronic devices. Several of those properties are…
Quantum materials have exhibited attractive electro-mechanical responses, but their piezoelectric coefficients are far from satisfactory due to the lack of fundamental mechanisms to benefit from the quantum effects. We discovered the valley…
The bulk piezoelectric response, as measured by the piezoelectric modulus tensor (\textbf{d}), is determined by a combination of charge redistribution due to strain and the amount of strain produced by the application of stress (stiffness).…
Two-dimensional (2D) ferroelectric semiconductors present opportunities for integrating ferroelectrics into high-density ultrathin nanoelectronics. Among the few synthesized 2D ferroelectrics, $\alpha$-In$_2$Se$_3$, known for its…
Flexible piezoelectric devices made of polymeric materials are widely used for micro- and nano-electro-mechanical systems. In particular, numerous recent applications concern energy harvesting. Due to the importance of computational…
Signal formation mechanism of Piezoresponse Force Microscopy of piezoelectric surface layers and thin films on stiff and elastically matched substrates is analyzed and thickness dependence of effective piezoelectric response, object…
Layered materials with non-centrosymmetric stacking order are attracting increasing interest due to the presence of ferroelectric polarization, which is dictated by weak interlayer hybridization of atomic orbitals. Here, we use density…
In this paper, a consistent theory is developed for size-dependent piezoelectricity in dielectric solids. This theory shows that electric polarization can be generated as the result of coupling to the mean curvature tensor, unlike previous…