Local probing of quantum materials at ultra-low temperature

NIST Gaithersburg

Moire systems in twisted multi-layer graphene and interface of oxide heterostructures with 2 D electron gas have rich phase diagram that is accessible upon controlling external parameters - magnetic and electric field. Scanning probe microscopy addresses spectroscopic properties locally, as well as provides topographical information. I will discuss two cases, demonstrating the capabilities of ultra-low temperature scanning probe techniques. First, I will show an example of employing magnetic field oscillations for characterizing the quantum geometry and quantum metric effects of narrow bands in twisted bilayer graphene using spatially resolved scanning tunneling spectroscopy. Second, I will discuss the local measurement of superconductivity at the LAO/STO interface using atomic force microscopy and mesoscopic electron transport.