相关论文: Structure and Born effective charge determination …
Ferroelectric-based photovoltaics have shown great promise as a source of renewable energy, thanks to their in-built charge separation capability, yet their efficiency is often limited by low charge carrier mobilities. In this work, we…
By means of density-functional simulations for half-doped manganites, such as pseudocubic Pr0.5Ca0.5MnO3 and bilayer PrCa2Mn2O7, we discuss the occurrence of ferroelectricity and we explore its crucial relation to the crystal structure and…
The Born effective charge, Z*, that describes the polarization created by collective atomic displacements, can be computed from first-principles following different techniques. We establish the connections existing between these different…
We derive first- and second-order piezoelectric coefficients for the zinc-blende III-V semiconductors, {Al,Ga,In}-{N,P,As,Sb}. The results are obtained within the Heyd-Scuseria-Ernzerhof hybrid-functional approach in the framework of…
The effect of external static charging on borophenes - 2D boron crystals - is investigated by using first principles calculations. The influence of the excess negative charge on the stability of the 2D structures is examined using a very…
We report first principles density functional calculations of the Born effective charges and electronic dielectric tensors for the relaxor PMN (PbMg1/3Nb2/3O3). Visualization of the Born charge tensors as charge ellipsoids have provided…
Ferroelectricity in atomically thin bilayer structures has been recently predicted1 and measured[2-4] in two-dimensional (2D) materials with hexagonal non-centrosymmetric unit-cells. Interestingly, the crystal symmetry translates lateral…
A modified model of metal-semiconductor contacts is applied to analyze the capacitance-voltage and current-voltage characteristics of metal-ferroelectric-metal structures. The ferroelectric polarization is considered as a sheet of surface…
We combine infrared absorption and Raman scattering spectroscopies to explore the properties of the heavy transition metal dichalcogenide 1T-HfS$_2$. We employ the LO-TO splitting of the $E_u$ vibrational mode along with a reevaluation of…
We investigate the chemical bonding characteristics of the transition metal dichalcogenides based on their static and dynamical atomic charges within Density Functional Theory. The dynamical charges of the trigonal transition metal…
Phosphorene has been rediscovered recently, establishing itself as one of the most promising two dimensional group-V elemental monolayers with direct band gap, high carrier mobility, and anisotropic electronic properties. In this letter,…
The Born effective charge, Z*, that describes the polarization created by collective atomic displacements, can be computed from first-principles by different techniques. Its band-by-band decomposition appeared recently as a powerful tool…
Bismuth ferrite is one of the most widely studied multiferroic materials because of its large ferroelectric polarisation coexisting with magnetic order at room temperature. Using density functional theory (DFT), we identify several…
Based on recent first-principles computations in perovskite compounds, especially BaTiO3, we examine the significance of the Born effective charge concept and contrast it with other atomic charge definitions, either static (Mulliken,…
The presence of a space charge region induces an internal electric field within the charged region that, in a ferroelectric material, would rotate the polarisations to align with the field. The strength of the induced field would therefore…
Density Functional Theory calculations have been performed to obtain lattice parameters, elastic constants, and electronic properties of ideal pyrochlores with the composition A$_2$B$_2$O$_7$ (where A=La,Y and B=Ti,Sn,Hf, Zr). Some thermal…
Large electron-electron Coulomb-interactions in correlated systems can lead to a periodic arrangement of localized electrons, the so called "charge-order". The latter is here proposed as a driving force behind ferroelectricity in iron…
Using projector augmented wave approach within the generalized gradient approximation, we have studied the structural property and electronic structure of ZrB12. The calculated lattice constants and bulk modulus are in good agreement with…
The properties of a ferroelectric, (001)-oriented, thin film clamped to a substrate are investigated analytically and numerically. The emphasis is on the tetragonal, polydomain, ferroelectric phase, using a three domain structure, as is…
Zigzag edges of neutral armchair-oriented Graphene Nano-Ribbons show states strongly localized at those edges. They behave as free radicals that can capture electrons during processing, increasing ribbon's stability. Thus, charging and its…