IR Spectroscopy of PbZr_1–xTi_xO₃ Material: A Complementary Experimental/Ab Initio Calculations Approach of a Solid Solution

Abstract

The perovskites lead zirconium titanate, PbZr1–x Ti x O3 (0 < x < 1), known as PZT, are solid solutions widely exploited for their strong piezoelectric properties. The utmost technological importance of this class of materials led to considerable activity on piezoelectric films from the experimental and simulation side. In a solid solution like PZT, the distribution of Zr and Ti atoms has no long-range ordering. Thus, these materials are highly challenging to model theoretically but also to investigate experimentally. In this study, we combine infrared (IR) absorption spectroscopy, with a Density Functional Theory method adapted for the calculation of solid solutions. The complexity of PZT material is reproduced through a combination of 2 × 2 × 2 supercells. Using such combination procedure, we show here that ab initio calculations shed light on the interpretation of IR measured absorption spectra for thin films of 5, 10, 45, 90 nm with composition x = 0.75 in PbZr1–x Ti x O3, as well as for pure PbZrO3 and PbTiO3. Furthermore, the simulation on the supercell structure was also performed for multiple compositions 0.5 ≤ x ≤ 1 in both tetragonal and cubic structures, allowing the understanding of the evolution of spectra with temperature (during the tetragonal to cubic phase transition) and with doping. This temperature study reveals the first experimental evidence of polar modes associated with the loss of spontaneous polarization in nanometer size PZT films, deposited on a silicon wafer. This combination of experimental and theoretical methods opens the way for the investigation of other solid solution materials.

High energy storage of PbZrO3 antiferroelectric thin films via constructing phase composition

“…Compared with other antiferroelectric materials, it has superior E BDS and fatigue resistance, and has more promising application prospects [14][15][16][17][18]. Additionally, there are methods to enhance the electrical properties of thin films by means of calculations and doping [19][20][21]. In recent years, there have been numerous reports on lead zirconate and PZ-based energy storage films, including (Pb, La) ZrO 3 , (Pb, La) (Zr, Ti) O 3 , (Pb, La) (Zr, Sn, Ti) O 3 and so on [22][23][24][25].…”

Quantification of Crystalline Phases in Hf0.5Zr0.5O2 Thin Films through Complementary Infrared Spectroscopy and Ab Initio Supercell Simulations

“…To be constant in the total number of atoms (24), the method implies the use of four unit cells for the t-phase (1 × 2 × 2, 2 × 1 × 2, and 2 × 2 × 1) and two unit cells for the m- and polar o-phases (1 × 1 × 2, 1 × 2 × 1, and 2 × 1 × 1) in the three directions of space. The supercell approach has been presented before for a similar solid solution system in refs and . In the present paper, FIR spectra were simulated for HZO in its polar o-phase (space group 29, Pca 2 1 ), for the t-phase (137, P 4 2 / nmc ), and for the most stable m-phase (14, P 2 1 / c ).…”

“…To thermodynamically evaluate the configuration’s distribution, the weighted average for each supercell crystal structure (m-, polar o-, and t-phases) of FIR spectra is presented in Figure . These reported theoretical IR spectra, here called I̅ N ( ν , T ) , are obtained from the I i (ν) IR spectra, corresponding to each of the N configurations for the 3 different supercells for each phase, following I̅ N ( ν , T ) = ∑ i = 1 N P i ( V , T ) × I i ( ν ) and by using the Boltzmann occupation probability, P i ( V , T ), given by P i ( V , T ) = m i .25em exp ( − E i k normalB T ) Ω .25em w i t h .25em normalΩ = ∑ i = 1 N m i .25em exp ( − E i k normalB T ) …”

“…To thermodynamically evaluate the configuration’s distribution, the weighted average for each supercell crystal structure (m-, polar o-, and t-phases) of FIR spectra is presented in Figure . These reported theoretical IR spectra, here called , are obtained from the I i (ν) IR spectra, corresponding to each of the N configurations for the 3 different supercells for each phase, following and by using the Boltzmann occupation probability, P i ( V , T ), given by …”

Second-order Jahn–Teller effect induced high-temperature ferroelectricity in two-dimensional NbO2X (X = I, Br)

“…[1][2][3][4] In the literature, many efforts have been made to develop perovskite-type oxides, such as BaTiO 3 , PbTiO 3 , PbZr 1-x Ti x O 3 , and La 1/3 NbO 3 in which the cations have an electron conguration of d 0 (Ti 4+ , Zr 4+ , Nb 5+ ). [5][6][7][8] Moreover, the spontaneous polarization of these compounds is usually induced by off-centering of cations which originates from the second-order Jahn-Teller (SOJT) effect. 9,10 SOJT-active cations have been shown to induce structural distortion, which would break the inversion symmetry, by anisotropic covalent bonding with ligands.…”