NV magnetometry of Van der Waals crystals at cryogenic temperatures

Advancing the frontiers of nanoscience and information technology hinges on the availability of novel tools for nanoscale sensing and imaging. Solid state, electronic spins offer a unique platform to implement robust,... [ view full abstract ]

Advancing the frontiers of nanoscience and information technology hinges on the availability of novel tools for nanoscale sensing and imaging. Solid state, electronic spins offer a unique platform to implement robust, high-performance quantum sensing devices, which go beyond what classical technologies can offer. The Quantum Sensing Group at Basel University has developed this idea into a robust technology based on nano-engineered diamond devices, which host single electronic spins for sensing. 

In this talk, I will describe the key principles underlying these novel quantum sensors and demonstrate their application to nanoscale imaging in cryogenic environments, which we have pioneered in the last years. Specifically, I will focus on applications of single spin magnetometry to nanoscale studies of Van der Waals crystals. Within the broad family of these two-dimensional materials, the recent discovery of intrinsic magnetic order in several compounds has recently generated significant interest. Our understanding of these materials however is still limited and, in particular, no experiment could thus far yield insight into the nanoscale nature of their magnetic order. Using NV magnetometry we demonstrated direct, nanoscale imaging of the magnetic texture in the magnetic insulator chromium triiodide. These results allowed us to determine the layer-dependant magnetisation strength as well as local defects and their impact on magnetisation reversal in a quantitative way for the first time. These results establish scanning single spin magnetometry as a powerful tool for applications in solid-state, mesoscopic physics and the nano-sciences in general and offer unprecedented insights into the nanoscale properties of magnetic Van der Waals crystals.