Chemical Profiles of the Oxides on Tantalum in State of the Art Superconducting Circuits.

Over the past decades, superconducting qubits have emerged as one of the leading hardware platforms for realizing a quantum processor. Consequently, researchers have made significant effort to understand the loss channels that limit the coherence times of superconducting qubits. A major source of loss has been attributed to two level systems that are present at the material interfaces.

Coherent correlation imaging for resolving fluctuating states of matter.

Fluctuations and stochastic transitions are ubiquitous in nanometre-scale systems, especially in the presence of disorder. However, their direct observation has so far been impeded by a seemingly fundamental, signal-limited compromise between spatial and temporal resolution. Here we develop coherent correlation imaging (CCI) to overcome this dilemma.

Imaging mesoscopic antiferromagnetic spin textures in the dilute limit from single-geometry resonant coherent x-ray diffraction.

The detection and manipulation of antiferromagnetic domains and topological antiferromagnetic textures are of central interest to solid-state physics. A fundamental step is identifying tools to probe the mesoscopic texture of an antiferromagnetic order parameter. In this work, we demonstrate that Bragg coherent diffractive imaging can be extended to study the mesoscopic texture of an antiferromagnetic order parameter using resonant magnetic x-ray scattering.

Real-space observation of fluctuating antiferromagnetic domains.

Magnetic domains play a fundamental role in physics of magnetism and its technological applications. Dynamics of antiferromagnetic domains is poorly understood, although antiferromagnets are expected to be extensively used in future electronic devices wherein it determines the stability and operational speed. Dynamics of antiferromagnets also features prominently in the studies of topological quantum matter.

Tuning spin excitations in magnetic films by confinement.

Spin excitations of magnetic thin films are the founding element for magnetic devices in general. While spin dynamics have been extensively studied in bulk materials, the behaviour in mesoscopic films is less known due to experimental limitations. Here, we employ resonant inelastic X-ray scattering to investigate the spectrum of spin excitations in mesoscopic Fe films, from bulk-like films down to three unit cells.

Resonant inelastic x-ray scattering study of [Formula: see text]-RuCl: a progress report.

Ru M-edge resonant inelastic x-ray scattering (RIXS) measurements of [Formula: see text] with 27 meV resolution reveals a spin-orbit exciton without noticeable splitting. We extract values for the spin-orbit coupling constant ([Formula: see text] meV) and trigonal distortion field energy ([Formula: see text] meV) which support the [Formula: see text] nature of [Formula: see text]. We demonstrate the feasibility of M-edge RIXS for 4d systems, which allows ultra high-resolution RIXS of 4d systems until instrumentation for L-edge RIXS improves.

Orbital Domain Dynamics in Magnetite below the Verwey Transition.

The metal-insulator phase transition in magnetite, known as the Verwey transition, is characterized by a charge-orbital ordering and a lattice transformation from a cubic to monoclinic structure. We use x-ray photon correlation spectroscopy to investigate the dynamics of this charge-orbitally ordered insulating phase undergoing the insulator-to-metal transition. By tuning to the Fe L_{3} edge at the (001/2) superlattice peak, we probe the evolution of the Fe t_{2g} orbitally ordered domains present in the low temperature insulating phase and forbidden in the high temperature metallic phase.

Habituation based synaptic plasticity and organismic learning in a quantum perovskite.

A central characteristic of living beings is the ability to learn from and respond to their environment leading to habit formation and decision making. This behavior, known as habituation, is universal among all forms of life with a central nervous system, and is also observed in single-cell organisms that do not possess a brain. Here, we report the discovery of habituation-based plasticity utilizing a perovskite quantum system by dynamical modulation of electron localization.

Charge-induced equilibrium dynamics and structure at the Ag(001)-electrolyte interface.

The applied potential dependent rate of atomic step motion of the Ag(001) surface in weak NaF electrolyte has been measured using a new extension of the technique of X-ray Photon Correlation Spectroscopy (XPCS). For applied potentials between hydrogen evolution and oxidation, the surface configuration completely changes on timescales of 10(2)-10(4) seconds depending upon the applied potential. These dynamics, directly measured over large areas of the sample surface simultaneously, are related to the surface energy relative to over or under potential.

Growth of arrays of oriented epitaxial platinum nanoparticles with controlled size and shape by natural colloidal lithography.

We developed a method for production of arrays of platinum nanocrystals of controlled size and shape using templates from ordered silica bead monolayers. Silica beads with nominal sizes of 150 and 450 nm were self-assembled into monolayers over strontium titanate single crystal substrates. The monolayers were used as shadow masks for platinum metal deposition on the substrate using the three-step evaporation technique.

Epitaxial oxide bilayer on Pt (001) nanofacets.

We observed an epitaxial, air-stable, partially registered (2 × 1) oxide bilayer on Pt (001) nanofacets [V. Komanicky, A. Menzel, K.