Tags - (6) scanning probe magnetism

Department(s)/lab(s): Physics | Feldman Lab @ Stanford
Summary:

Feldman's group uses scanning NV-diamond magnetometry -- imaging local magnetic fields with a single spin at the tip of a scanning probe -- to visualize currents, magnetism, and correlated-electron order in moire and other quantum materials at the nanoscale, extending the sensitivity/resolution tradeoff of ensemble NV-diamond sensing (DEER/T1 protocols at pT/√Hz) down to single-spin, single-defect imaging.

Department(s)/lab(s): Department of Materials (D-MATL) | Magnetism and Interface Physics Group (Gambardella) @ ETH Zurich
Summary:

Gambardella leads the Magnetism and Interface Physics group at ETH D-MATL. Research directions: (1) Scanning probe magnetometry — using NV-center cantilevers (collaboration with Degen) and magneto-optical Kerr microscopy to image spin textures (skyrmions, domain walls) in thin-film heterostructures with sub-100 nm resolution; (2) Spin-orbit torques — current-induced magnetization switching via interfacial spin-orbit coupling; spin Hall and Rashba effects for spintronic devices; (3) Single-atom magnetism — STM and X-ray absorption for element-specific orbital and spin moments of individual atoms on surfaces; (4) XMCD at synchrotron — quantitative element-specific magnetic spectroscopy. Quantum sensing angle: spin-orbit driven phenomena, high-resolution magnetic imaging.

Department(s)/lab(s): Applied Physics | Moler Group @ Stanford
Summary:

Moler's lab builds scanning SQUID microscopes -- magnetic-flux sensors cooled to cryogenic temperatures and scanned within microns of a sample -- to image supercurrents, vortices, and interfacial magnetism in unconventional superconductors and topological materials with sensitivity and spatial resolution that complements ensemble NV-diamond magnetometry (which reaches pT/√Hz via DEER/T1-type protocols) at a very different length and field scale.

Department(s)/lab(s): School of Physics | Rogge Single Dopant Spectroscopy Group @ UNSW
Summary:

Rogge (formerly Delft) works on the spectroscopy of individual dopant atoms in silicon: using transport, STM and microwave spectroscopy to read out the orbital, valley and spin structure of single donors and acceptors, including their coupling to strain, electric fields and each other. The group has mapped the wavefunctions of individual dopants and used acceptor spin-orbit coupling for electric-field-driven spin control. This is single-quantum-object measurement rather than device engineering. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — single-donor spectroscopy is the silicon analogue of single-NV work: the same questions about coherence, bath engineering and readout fidelity that fix pT/sqrt(Hz) ensemble performance appear here in a platform where the sensor can be placed with atomic precision and interrogated electrically rather than optically.

Department(s)/lab(s): School of Physics | Atomic Fabrication Facility (Simmons) @ UNSW
Summary:

Simmons pioneered atomic-precision fabrication in silicon: hydrogen-resist STM lithography, phosphine dosing and epitaxial silicon overgrowth to place individual dopant atoms with sub-nanometre accuracy, then measure them at millikelvin. The programme has produced single-atom transistors, precision dopant arrays used as analogue quantum simulators, and the largest atom-scale device platform in the world; she also founded Silicon Quantum Computing Pty Ltd. The sensing-relevant capability is the single-electron transistor as an exquisitely sensitive electrometer, capable of resolving individual charge transitions and mapping local electrostatic potential at the atomic scale. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — her SET electrometry is the charge-domain counterpart to magnetic NV sensing at pT/sqrt(Hz): both are single-quantum-object detectors whose performance is limited by back-action and by the noise of the readout chain. Very large group, strongly fabrication-oriented and commercially entangled, which cuts against the stated preference for sensitivity-limited rather than fabrication-limited work.

Department(s)/lab(s): Physics | Yacoby Lab @ Harvard
Summary:

Yacoby's lab develops scanning-probe quantum sensors, most notably scanning single-NV-center magnetometers and SQUID-on-tip probes, to image nanoscale magnetic textures and current flow in quantum materials at cryogenic and millikelvin temperatures. This scanning-probe approach extends the sensitivity and spatial resolution of NV ensemble quantum sensing experiments (DEER, nanoscale NMR, T1 relaxometry), which established pT/√Hz-class magnetometry, down to single-spin, nanometer-scale imaging of individual quantum materials.