Fast Spectroscopic Mapping of two dimensional quantum materials

The functionality of devices is built on the precise knowledge of its composing materials. This insight stems from extensive theoretic and spectroscopic studies. The latter are carried out against additional degrees of freedom, such as: magnetic field, location, temperature, or doping. Such measurement involve two serial tasks, making spectroscopic mapping excruciatingly slow. Here we demonstrate orders of magnitude faster measurements through our combination of sparse sampling and parallel spectroscopy. We illustrate our concept using quasiparticle interference imaging of Au(111) and Bi₂Sr₂CaCu₂O_8+δ (Bi2212) with a scanning tunneling microscope. We first demonstrate parallel spectroscopy and sparse sampling individually and then combine both for an exponential speed-up. Our method is accessible and straightforward to implement with existing setups. It can be extended to other measurement programs, such as gate spectroscopy. The profound speed advantage of our fast spectroscopic mapping promotes the discovery of novel quantum materials.