Coherent spin-control of = 1 vanadium and molybdenum complexes.

The burgeoning field of quantum sensing hinges on the creation and control of quantum bits. To date, the most well-studied quantum sensors are optically active, paramagnetic defects residing in crystalline hosts. We previously developed analogous optically addressable molecules featuring a ground-state spin-triplet centered on a Cr ion with an optical-spin interface.

Tunable Cr Molecular Color Centers.

The inherent atomistic precision of synthetic chemistry enables bottom-up structural control over quantum bits, or qubits, for quantum technologies. Tuning paramagnetic molecular qubits that feature optical-spin initialization and readout is a crucial step toward designing bespoke qubits for applications in quantum sensing, networking, and computing. Here, we demonstrate that the electronic structure that enables optical-spin initialization and readout for = 1, Cr(aryl), where aryl = 2,4-dimethylphenyl (), -tolyl (), and 2,3-dimethylphenyl (), is readily translated into Cr(alkyl) compounds, where alkyl = 2,2,2-triphenylethyl (), (trimethylsilyl)methyl (), and cyclohexyl ().

Imaging Polarity in Two Dimensional Materials by Breaking Friedel's Law.

Friedel's law guarantees an inversion-symmetric diffraction pattern for thin, light materials where a kinematic approximation or a single-scattering model holds. Typically, breaking Friedel symmetry is ascribed to multiple scattering events within thick, non-centrosymmetric crystals. However, two-dimensional (2D) materials such as a single monolayer of MoS can also violate Friedel's law, with unexpected contrast between conjugate Bragg peaks.

Electron ptychography of 2D materials to deep sub-ångström resolution.

Aberration-corrected optics have made electron microscopy at atomic resolution a widespread and often essential tool for characterizing nanoscale structures. Image resolution has traditionally been improved by increasing the numerical aperture of the lens (α) and the beam energy, with the state-of-the-art at 300 kiloelectronvolts just entering the deep sub-ångström (that is, less than 0.5 ångström) regime.

High Dynamic Range Pixel Array Detector for Scanning Transmission Electron Microscopy.

We describe a hybrid pixel array detector (electron microscope pixel array detector, or EMPAD) adapted for use in electron microscope applications, especially as a universal detector for scanning transmission electron microscopy. The 128×128 pixel detector consists of a 500 µm thick silicon diode array bump-bonded pixel-by-pixel to an application-specific integrated circuit. The in-pixel circuitry provides a 1,000,000:1 dynamic range within a single frame, allowing the direct electron beam to be imaged while still maintaining single electron sensitivity.