Birefringence induced by antiferroelectric switching in transparent polycrystalline PbZr0.95Ti0.05O3 filmBiswas, Pranab ; ; et alin Physical Review Materials (2022), 6(9), 091403 The most characteristic functional property of antiferroelectric materials is the possibility to induce a phase transition from a nonpolar to a polar phase by an electric field. Here, we investigate the ... [more ▼] The most characteristic functional property of antiferroelectric materials is the possibility to induce a phase transition from a nonpolar to a polar phase by an electric field. Here, we investigate the effect of this field-induced phase transition on the birefringence change of PbZr0.95Ti0.05O3. We use a transparent polycrystalline PbZr0.95Ti0.05O3 film grown on PbTiO3/HfO2/SiO2 with interdigitated electrodes to directly investigate changes in birefringence in a simple transmission geometry. In spite of the polycrystalline nature of the film and its moderate thickness, the field-induced transition produces a sizable effect observable under a polarized microscope. The film in its polar phase is found to behave like a homogeneous birefringent medium. The time evolution of this field-induced birefringence provides information about irreversibilities in the antiferroelectric switching process and its slow dynamics. The change in birefringence has two main contributions: One that responds briskly and a slower one that rises and saturates over a period of as long as 30 min. Possible origins for this long saturation and relaxation times are discussed. [less ▲] Detailed reference viewed: 97 (5 UL) Increasing bulk photovoltaic current by strain tuning; Kreisel, Jens ; in Science Advances (2019), 5(3), Photovoltaic phenomena are widely exploited not only for primary energy generation but also in photocatalytic, photoelectrochemistry, or optoelectronic applications. In contrast to the interface-based ... [more ▼] Photovoltaic phenomena are widely exploited not only for primary energy generation but also in photocatalytic, photoelectrochemistry, or optoelectronic applications. In contrast to the interface-based photovoltaic effect of semiconductors, the anomalous or bulk photovoltaic effect in ferroelectrics is not bound by the Shockley-Queisser limit and, thus, can potentially reach high efficiencies. Here, we observe in the example of an Fe-doped LiNbO3 bulk single crystal the existence of a purely intrinsic ``piezophotovoltaic'' effect that leads to a linear increase in photovoltaic current density. The increase reaches 75 under a low uniaxial compressive stress of 10 MPa, corresponding to a strain of only 0.005\%. The physical origin and symmetry properties of the effect are investigated, and its potential for strain-tuned efficiency increase in nonconventional photovoltaic materials is presented. [less ▲] Detailed reference viewed: 210 (5 UL) |
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