Self-consistently derived sample permittivity in stabilization of ferroelectricity due to charge accumulated at interfaces

Abstract

Recently, a simple model was proposed for the microscopic energy associated to the ferroelectric phase, to be used in a statistical approach in order to derive the equations of state...

Molecular adsorption–desorption of carbon monoxide on ferroelectric BaTiO3(001)

“…The two independent ratios cannot be used to uniquely determine three parameters, l O /c, l Ti /c, and l Ba /c. The Monte Carlo method was used to find sets of these three parameters, giving the closest match for I Ba /I Ti E 2.94 and I O /I Ba E 1.45, by estimating the values given by eqn (7) and (8). The values that give the closest match to the experimental intensity ratios over 10 7 iterations over a wide range of IMFPs (in c units) were retained.…”

“…Only recently, a microscopic model for ferroelectricity in thin films with a single domain structure was proposed, highlighting the definitory role of charges accumulated at surfaces and interfaces. [7][8][9] The second difficulty is related mainly to the possibility of working on atomically clean model systems, such as ferroelectric single crystals, in order to quantitatively assess surface adhesion and dissociation. Moreover, such results were lacking until recently, when carbon monoxide adsorption and dissociation on a strong ferroelectric single crystalline thin film, lead zirconate titanate (PZT), were followed-up using photoelectron spectroscopic techniques.…”

Experimental Band Structure of Pb(Zr,Ti)O3: Mechanism of Ferroelectric Stabilization

“…Such opposite variation is not expected for the W f -dependent band alignment at metal|FE interfaces where the metal band structure and its V(z) should in principle remain immune to the interface formation. This rather points at a FE-induced alteration of the carrier density into LSMO and Nb:STO substrates as well, where close to the interface with PZT, the substrate supplies positive/negative carriers to screen the fixed interface dipole charges [24,58] and stabilize the UP/DW FE state. Accordingly, V(z) in Figure 4b describes the positive charging into Nb:STO close to the interface to compensate the FE polarization pointing away from the substrate (P+), while a negatively charged LSMO interface stabilizes the FE state pointing toward the substrate (P−).…”

“…Intrinsic mechanisms involve migration across the FE material [24,25] of the already existing positive (holes, ionized donor impurities, or p-type dopants) and negative charges (electrons, ionized acceptor impurities, or n-type dopants), intentionally introduced [26] or resulting from self-doping. [27] Such charge reorganization is accompanied by band bending which manifests either in the outer material for purely extrinsic compensation or within the FE in the case of intrinsic mechanisms.…”