Related papers: Interplay between Ferroelectricity and Metallicity…
Titanates with the perovskite structure, including ferroelectrics (e.g., BaTiO$_3$) and ferromagnetic ones (e.g., YTiO$_3$), are important functional materials. Recent theoretical studies predicted multiferroic states in strained EuTiO$_3$…
We report a systematic investigation, together with a theoretical analysis, of the resistivity and Hall effect in single crystals of Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$, over a wide doping range. We find a surprisingly great disparity…
A comparative study of the electrical and optical properties has been done on 3d-doped TiO$_2$. Ti$_{1-x}$M$_x$O$_2$ (M= Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) powder and its corresponding pellets, with doping concentration $x= 0.05$. The…
Fluorite structure ferroelectrics, especially hafnium oxide, are widely investigated for their application in non-volatile memories, sensors, actuators, RF devices and energy harvesters. Due to the metastable nature of the ferroelectric…
Properties of (BaTiO$_3$)$_1$/(BaZrO$_3$)$_n$ ferroelectric superlattices (SLs) with $n = {}$1--7 grown in the [001] direction are calculated from first principles within the density functional theory. It is revealed that the…
We investigate how field-effect doping affects the structural properties, the electronic structure and the Hall coefficient of few-layers transition metal dichalcogenides by using density-functional theory. We consider mono-, bi-, and…
Micrometric domains of precise ferroelectric polarization have been written into a 20 nm thick epitaxial thin film of BaTiO3(001) (BTO) on a Nb doped SrTiO3 (STO) substrate using PiezoForce Microscopy (PFM). The domain dependent electronic…
To optimize the performance of multifunctional carbon nanotube-ferroelectric devices, it is necessary to understand both the polarization and charge dynamics effects on their transconductance. Directly comparing ferroelectric…
We use first-principles methods to study doped strong ferroelectrics (taking BaTiO$_3$ as a prototype). Here we find a strong coupling between itinerant electrons and soft polar phonons in doped BaTiO$_3$, contrary to Anderson/Blount's…
We present a strategy for increasing thermoelectric performance by invoking ferroelectric distortion in a transition-metal oxide. By using an ab initio calculation approach with the Boltzmann transport equation, a large Seebeck coefficient…
We report the magnetic and electrical characteristics of a polycrystalline specimen of FeTiO3 synthesized at high pressure that is isostructural with acentric LiNbO3 (LBO). Piezoresponse force microscopy, optical second harmonic generation,…
The possibility of reconciliation between seemingly mutually exclusive properties in one system can not only lead to theoretical breakthroughs but also potential novel applications. The research on the coexistence of two purportedly…
We report \emph{ab initio} predictions on the proper multiferroic (ferromagnetic, insulating and ferroelectric) character of PbTiO$_{3}$ doped with vanadium. V impurities coupled ferromagnetically carry a magnetization of 1 $\mu_{\rm B}$…
Recent advances in electrostatic gating provide a novel way to modify the carrier concentration in materials via electrostatic means instead of chemical doping, thus minimizing the impurity scattering. Here, we use first-principles Density…
For the ferroelectric perovskite compounds BaTiO3 and PbTiO3, we have studied the effects of external electric fields on the structural properties of the (001) surfaces. The field-induced changes in the surface interlayer spacings and…
We study the electrocaloric effect in the classic ferroelectric BaTiO3 through a series of phase transitions driven by applied electric field and temperature. We find both negative and positive electrocaloric effects, with the negative…
SrTiO$_{3}$, a quantum paraelectric, becomes a metal with a superconducting instability after removal of an extremely small number of oxygen atoms. It turns into a ferroelectric upon substitution of a tiny fraction of strontium atoms with…
Ordinary doping by electrons (holes) generally means that the Fermi level shifts towards the conduction band (valence band) and that the conductivity of free carriers increases. Recently, however, some peculiar doping characteristics were…
It has been observed that impurity doping and/or ion-beam-induced damage in high $T_{c}$ superconductors cause a metal-insulator transition and thereby suppress the critical temperature. Based on our recent theory of the weak localization…
We report density functional calculations of the electronic structure and Fermi surface of the BaFe$_2$As$_2$ and LiFeAs phases including doping via the virtual crystal approximation. The results show that contrary to a rigid band picture,…