Strain-stabilized superconductivity.

Superconductivity is among the most fascinating and well-studied quantum states of matter. Despite over 100 years of research, a detailed understanding of how features of the normal-state electronic structure determine superconducting properties has remained elusive. For instance, the ability to deterministically enhance the superconducting transition temperature by design, rather than by serendipity, has been a long sought-after goal in condensed matter physics and materials science, but achieving this objective may require new tools, techniques and approaches.

Site-specific spectroscopic measurement of spin and charge in (LuFeO)/(LuFeO) multiferroic superlattices.

Interface materials offer a means to achieve electrical control of ferrimagnetism at room temperature as was recently demonstrated in (LuFeO)/(LuFeO) superlattices. A challenge to understanding the inner workings of these complex magnetoelectric multiferroics is the multitude of distinct Fe centres and their associated environments. This is because macroscopic techniques characterize average responses rather than the role of individual iron centres.

Direct Visualization of Trimerized States in 1T^{'}-TaTe_{2}.

Transition-metal dichalcogenides containing tellurium anions show remarkable charge-lattice modulated structures and prominent interlayer character. Using cryogenic scanning transmission electron microscopy (STEM), we map the atomic-scale structures of the high temperature (HT) and low temperature (LT) modulated phases in 1T^{'}-TaTe_{2}. At HT, we directly show in-plane metal distortions which form trimerized clusters and staggered, three-layer stacking.

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.

Infrared nano-spectroscopy of ferroelastic domain walls in hybrid improper ferroelectric CaTiO.

Ferroic materials are well known to exhibit heterogeneity in the form of domain walls. Understanding the properties of these boundaries is crucial for controlling functionality with external stimuli and for realizing their potential for ultra-low power memory and logic devices as well as novel computing architectures. In this work, we employ synchrotron-based near-field infrared nano-spectroscopy to reveal the vibrational properties of ferroelastic (90[Formula: see text] ferroelectric) domain walls in the hybrid improper ferroelectric Ca[Formula: see text]Ti[Formula: see text]O[Formula: see text].