Understanding the nature of electronic states requires access to a variety of fundamental observables. Some can be extracted directly from a well designed sample–resistance and density of states, e.g.–but others require specialized tools.  We are building a nanoSQUID [4] microscope that will allow nanoscale mapping of magnetic [4] and thermal [5] properties, based on a superconducting quantum interference device fabricated at the tip of a quartz pipette. The image at right shows an electron micrograph of one such sensor, as well as an optical image of the pipette attached to a quartz tuning fork, used to implement topographic feedback. We anticipate best spatial resolution of ~40 nm, with sub-single spin sensitivity and high thermal sensitivity in the cryogenic temperature range; these features make nSOTs unique among scanning probes.  The first microscope, currently under construction, will operate at 4K and in magnetic fields of several tesla, allowing studies of magnetic materials and thermal transport in nanoscale systems, and a 50 millikelvin is being designed.

Unlike conventional planar scanned SQUIDs, nSOTs work in large magnetic fields (as shown in the response curve image).  Our immediatescientific projects include vortex dynamics in 2D superconductors, magnetism in low dimensional materials and heterostructures, and thermal transport properties in mesoscopic systems.

[4] Vasyukov et al., Nature Nanotechnology 8:639-644 (2013).
[5] Halbertal et al., Nature 539:407–410 (2016)