Deflecting Dendrites by Introducing Compressive Stress in LiLaZrO Using Ion Implantation.

Lithium dendrites belong to the key challenges of solid-state battery research. They are unavoidable due to the imperfect nature of surfaces containing defects of a critical size that can be filled by lithium until fracturing the solid electrolyte. The penetration of Li metal occurs along the propagating crack until a short circuit takes place.

Kerr-lens mode-locked 49-fs Tm:YScO single-crystal laser at 2.1 µm.

We report on a continuous wave (CW) and Kerr-lens mode-locked (KLM) Tm:YScO single-crystal laser centered at 2.1 µm. Efficient CW laser operation with a maximum slope efficiency of 51% was achieved under in-band pumping by an Er:Yb fiber master oscillator power amplifier (MOPA).

Li/H exchange of LiLaZrO single and polycrystals investigated by quantitative LIBS depth profiling.

LiLaZrO (LLZO) garnets are highly attractive to be used as solid electrolyte in solid-state Li batteries. However, LLZO suffers from chemical interaction with air and humidity, causing Li/H exchange with detrimental implication on its performance, processing and scalability. To better understand the kinetics of the detrimental Li/H exchange and its dependence on microstructural features, accelerated Li/H exchange experiments were performed on single crystalline and polycrystalline LLZO, exposed for 80 minutes to 80 °C hot water.

Non-volatile electric-field control of inversion symmetry.

Competition between ground states at phase boundaries can lead to significant changes in properties under stimuli, particularly when these ground states have different crystal symmetries. A key challenge is to stabilize and control the coexistence of symmetry-distinct phases. Using BiFeO layers confined between layers of dielectric TbScO as a model system, we stabilize the mixed-phase coexistence of centrosymmetric and non-centrosymmetric BiFeO phases at room temperature with antipolar, insulating and polar semiconducting behaviour, respectively.

Spectroscopy and 2.1 µm laser operation of Czochralski-grown Tm:YScO crystals.

We report on growth, temperature-dependent spectroscopy, and laser experiments of Tm-doped YScO mixed sesquioxide crystals. For the first time, cm-scale laser quality Tm:YScO crystals with 2.2 at.

Liberating a hidden antiferroelectric phase with interfacial electrostatic engineering.

Antiferroelectric materials have seen a resurgence of interest because of proposed applications in a number of energy-efficient technologies. Unfortunately, relatively few families of antiferroelectric materials have been identified, precluding many proposed applications. Here, we propose a design strategy for the construction of antiferroelectric materials using interfacial electrostatic engineering.

Investigating the electrochemical stability of LiLaZrO solid electrolytes using field stress experiments.

Cubic LiLaZrO (LLZO) garnets are among the most promising solid electrolytes for solid-state batteries with the potential to exceed conventional battery concepts in terms of energy density and safety. The electrochemical stability of LLZO is crucial for its application, however, controversial reports in the literature show that it is still an unsettled matter. Here, we investigate the electrochemical stability of LLZO single crystals by applying electric field stress macro- and microscopic ionically blocking Au electrodes in ambient air.

Electron ptychography achieves atomic-resolution limits set by lattice vibrations.

Transmission electron microscopes use electrons with wavelengths of a few picometers, potentially capable of imaging individual atoms in solids at a resolution ultimately set by the intrinsic size of an atom. However, owing to lens aberrations and multiple scattering of electrons in the sample, the image resolution is reduced by a factor of 3 to 10. By inversely solving the multiple scattering problem and overcoming the electron-probe aberrations using electron ptychography, we demonstrate an instrumental blurring of less than 20 picometers and a linear phase response in thick samples.

Wet-Environment-Induced Structural Alterations in Single- and Polycrystalline LLZTO Solid Electrolytes Studied by Diffraction Techniques.

LiLaZrO (LLZO) is one of the potential candidates for Li metal-based solid-state batteries owing to its high Li conductivity (≈10 S cm) at room temperature and large electrochemical stability window. However, LLZO undergoes protonation under the influence of moisture-forming LiCO layers, thereby affecting its structural and transport properties. Therefore, a detailed understanding on the impact of the exchange of H on Li sites on structural alteration and kinetics under the influence of wet environments is of great importance.

Targeted chemical pressure yields tuneable millimetre-wave dielectric.

Epitaxial strain can unlock enhanced properties in oxide materials, but restricts substrate choice and maximum film thickness, above which lattice relaxation and property degradation occur. Here we employ a chemical alternative to epitaxial strain by providing targeted chemical pressure, distinct from random doping, to induce a ferroelectric instability with the strategic introduction of barium into today's best millimetre-wave tuneable dielectric, the epitaxially strained 50-nm-thick n = 6 (SrTiO)SrO Ruddlesden-Popper dielectric grown on (110) DyScO. The defect mitigating nature of (SrTiO)SrO results in unprecedented low loss at frequencies up to 125 GHz.

Ferroelectric Domain Walls in PbTiO Are Effective Regulators of Heat Flow at Room Temperature.

Achieving efficient spatial modulation of phonon transmission is an essential step on the path to phononic circuits using "phonon currents". With their intrinsic and reconfigurable interfaces, domain walls (DWs), ferroelectrics are alluring candidates to be harnessed as dynamic heat modulators. This paper reports the thermal conductivity of single-crystal PbTiO thin films over a wide variety of epitaxial-strain-engineered ferroelectric domain configurations.

Ultra-slow light propagation by self-induced transparency in ruby in the superhyperfine limit.

Self-induced transparency is reported for circularly polarized light in the R(-3/2) line of a 30 ppm ruby (α-AlO:Cr) at 1.7 K in a magnetic field of B‖c=4.5  T.

Characterization of powellite-based solid solutions by site-selective time resolved laser fluorescence spectroscopy.

We present a comprehensive study of the solid solution system Ca2(MoO4)2-NaGd(MoO4)2 on the molecular scale, by means of site-selective time resolved laser fluorescence spectroscopy (TRLFS). Eu(3+) is used as a trace fluorescent probe, homogeneously substituting for Gd(3+) in the solid solution crystal structure. Site-selective TRLFS of a series of polycrystalline samples covering the whole composition range of the solid solution series from 10% substitution of Ca(2+) to the NaGd end-member reveals it to be homogeneous throughout the whole range.