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Left: SEM image of a single crystalline diamond nanopillar probe with a single NV centre at its tip, able to scan within tens of nanometres of a sample surface. The nanopillar is used as the tip of an atomic force microscope, enabling magnetometry measurements of unprecendented sensitivity and spatial resolution. The device was fabricated using low-energy ion implantation for NV creation, several electron-beam lithography steps, followed by reactive ion etching. Our scanning diamond nanopillars have typical diameters of ~200 nm and lengths of 1 μm and are fabricated on few-micrometre-sized diamond platforms. For more information please see P. Maletinsky et al. Nature Nanotechnology 7 320-324 (2012). and M. S. Grinolds et al. Nature Physics 9 215-219 (2013).
Middle left: The inverse compressibility dμ/dn as a function of carrier density n and magnetic field B. It is most interesting to note the appearance of incompressible peaks at fractional filling factors, the strongest of which emerge around B = 1 T. This data comes from a local electronic compressibility measurement of a suspended graphene flake performed with a scanning single-electron transistor (SET)—which is about 100 nm in size and is held 50 to 150 nm above the graphene flake. Our local technique provides a direct thermodynamic measurement of bulk sample properties and is sensitive to weak effects that may be obscured by disorder in global transport studies. For more information please see B.E. Feldman et al. Science 337 1196-1199 (2012).
Middle right: An artist's depiction of the capacitive interaction between two singlet-triplet qubits. This controlled two-qubit operation between singlet-triplet qubits used a dynamically decoupled sequence to maintain the two-qubit coupling while decoupling each qubit from its fluctuating environment. The two-qubit gate that has been demonstrated is a first step towards developing a larger infrastructure for quantum information processing. For more information please see M.D. Shulman et al. Science 336 202-205 (20012).
Right: Measurements of supercurrents conﬁned to edge states in HgTe/HgCdTe quantum well heterostructures. A Josephson junction consisting of a 7.5 nm-wide quantum well is fabricated along with a tunable topgate used to manipulate the overall behavior of the junction. As the bulk carriers are depleted, the supercurrent density develops peaks due to the presence of the helical edges. This evolution toward edge-dominated transport appears in the interference pattern as a narrowing central lobe width and more pronounced side lobe amplitudes. For more information please see S. Hart et al. arxiv : 1312.2559 (2013).