Role of polaron hopping in leakage current behavior of a SrTiO3 single crystal

Abstract

We studied the ionic/electronic transport and resistance degradation behavior of dielectric oxides by solving the electrochemical transport equations. Here, we took into account the non-periodical boundary conditions for the transport equations using the Chebyshev collocation algorithm. A sandwiched NijSrTiO 3 jNi capacitor is considered as an example under the condition of 1.0 V, 1.0 lm thickness for SrTiO 3 layer, and a temperature of 150 C. The applied voltage resulted in the migration of ionic defects (oxygen vacancies) from anode towards cathode. The simulated electric potential profile at steady state is in good agreement with the recent experimental observation. We introduced the possibility of polaron-hopping between Ti 3þ and Ti 4þ at the electrode interface. It is shown that both the oxygen vacancy transport and the polaron-hopping contribute to the resistance degradation of single crystal SrTiO 3 , which is consistent with the experimental observations. V C 2013 AIP Publishing LLC. [http://dx.

Ferroelectric or non-ferroelectric: Why so many materials exhibit “ferroelectricity” on the nanoscale

“…306,396,397 Recent emergence of phase field models for combined ferroelectric-semiconductor and ferroelectric-surface electrochemical behaviors offers numerous future opportunities. 398,399 However, the progress in resonance-enhanced PFM modes and introduction of low-noise platforms by commercial vendors enabled the PFM measurements in systems with much weaker electromechanical responses. Combined with the theoretical developments predicting a broad set of electromechanical and ferroelectric phenomena on the nanoscale, this led to a broad gamut of studies exploring ferroelectric-like behavior in dimensionally confined ferroelectrics, nonferroelectric oxides, and macromolecular and biological systems.…”

Dielectric Relaxation in Zr‐Doped SrTiO3 Ceramics Sintered in N2 with Giant Permittivity and Low Dielectric Loss

“…In our previous work, we reported that SrTiO 3 (ST) ceramics sintered in N 2 have a weak temperature‐ and frequency‐dependent giant permittivity (>10 4 ) and a very low dielectric loss (<0.02) over a broad temperature range from −100°C to 200°C, which is due to giant defect dipoles generated by the Ti 3+ ions and fully ionized oxygen vacancies. A large number of studies revealed that oxygen vacancies play a decisive role in determining the dielectric properties of ST‐based ceramics . In the temperature range below room temperature (RT), the dielectric relaxation usually manifests as a polar on relaxation due to electron (created by the ionization of oxygen vacancies) hopping between polyvalent ions.…”

Phase-field modeling of chemical control of polarization stability and switching dynamics in ferroelectric thin films

“…31 The material constants and energy coefficients of PZT thin film are collected from literature. [32][33][34] The parameters used in the simulation are listed in Table II surface ions are assumed to lie in a plane on top of the dielectric layer, at a distance λ above the film surface, and remain zero elsewhere, which corresponds to the physical size of the ions.…”