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We systematically study three-terminal InSb-Al nanowire devices by using radio-frequency reflectometry. Tunneling spectroscopy measurements on both ends of the hybrid nanowires are performed while systematically varying the chemical potential, magnetic field and junction transparencies. Identifying the lowest-energy state allows for the construction of lowest- and zero-energy state diagrams, which show how the states evolve as a function of the aforementioned parameters. Importantly, comparing the diagrams taken for each end of the hybrids enables the identification of states which do not coexist simultaneously, ruling out a significant amount of the parameter space as candidates for a topological phase. Furthermore, altering junction transparencies filters out zero-energy states sensitive to a local gate potential. Such a measurement strategy significantly reduces the time necessary to identify a potential topological phase and minimizes the risk of falsely recognizing trivial bound states as Majorana zero modes., Main text: 12 pages, 9 figures. SupplementaryMaterials: 12 pages, 14 figures

Liquid phase transmission electron microscopy has become a powerful tool for imaging the structure and dynamics of materials in solution. Direct observation of material formation, modification and operation has provided unique insights into the chemistry that governs the structure–property relationships of materials with myriad applications including optical, magnetic and electronic materials. However, full control over the reaction environment inside the microscope, especially the solution temperature and concentration of reactants, remains challenging and has limited the application of this high-resolution methodology. Here we present the ‘Stream Liquid Heating Holder’, a complete system for liquid phase experiments at elevated temperature inside the transmission electron microscope. This system features a unique on-chip flow channel combined with a microheater. The channel enables direct flow over the imaging area and rapid replenishment of the solution inside the Nano-cell with simultaneous heating to more than 100 °C. The capabilities of the system are demonstrated by studying the liquid flow dynamics and comparing the temperature dependent etching kinetics of silica nanoparticles by in situ liquid phase electron microscopy to in-flask experiments.

The field of electrochemistry promises solutions for the future energy crisis and environmental deterioration by developing optimized batteries, fuel-cells and catalysts. Combined with in situ transmission electron microscopy (TEM), it can reveal functional and structural changes. A drawback of this relatively young field is lack of reproducibility in controlling the liquid environment while retaining the imaging and analytical capabilities. Here, a platform for in situ electrochemical studies inside a TEM with a pressure-driven flow is presented, with the capability to control the flow direction and to ensure the liquid will always pass through the region of interest. As a result, the system offers the opportunity to define the mass transport and control the electric potential, giving access to the full kinetics of the redox reaction. In order to show the benefits of the system, copper dendrites are electrodeposited and show reliable electric potential control. Next, their morphology is changed by tuning the mass transport conditions. Finally, at a liquid thickness of approximately 100 nm, the diffraction pattern revealed the 〈1,1,1〉 planes of the copper crystals, indicating an atomic resolution down to 2.15 A. Such control of the liquid thickness enabled elemental mapping, allowing us to distinguish the spatial distribution of different elements in liquid.

Commercial purity vanadium with an initial grain size of ~27 μm and a Vickers microhardness of Hv≈85 was processed by high-pressure torsion (HPT) under a pressure of 6.0 GPa at room temperature through 1/2 to 10 turns. After processing through 10 turns, some samples were immediately subjected to a short-term annealing (15 min) at different temperatures from 773 to 1173 K. The microstructures developed in HPT and in HPT plus post-HPT annealing were characterized by electron backscatter diffraction (EBSD). Processing by HPT for 10 turns gave a refined grain size of ~410 nm and an increased hardness of Hv≈240. Post-HPT annealing demonstrated that the ultrafine grained vanadium has good thermal stability up to at least 873 K. Tensile testing at room temperature gave an ultimate tensile strength of ~920 MPa after 10 turns of HPT with an elongation of ~29%. These results show HPT processing produces superior mechanical properties in vanadium by comparison with processing by ECAP or ECAP plus cryorolling.