The Cryogenic Quantum Twisting Microscope, Part I

Measuring the energy-momentum dispersion relation in quantum materials can provide key insights into their strongly correlated electronic phenomena. We have recently demonstrated a new type of a scanning probe microscope – the Quantum Twisting Microscope (QTM) – capable of measuring electrons in momentum space in a similar way to the way a scanning tunneling microscope (STM) measures electrons in real-space. The QTM is based on a van-der-Waals (vdW) heterostructure on a tip, which, when brought into contact with another vdW sample, allows electrons to tunnel into it at many locations simultaneously, and quantum coherently. This makes the QTM tip a scanning electronic interferometer. With an extra twist degree of freedom, this microscope becomes a momentum-resolving local scanning probe. The first version of our microscope operated at room temperature, and already there demonstrated quantum coherence at its tip, and the ability to image the dispersions of monolayer and twisted bilayer graphene¹. Yet, even more exciting physics can emerge if the QTM could be generalized to cryogenic temperatures, where quantum mechanics and strong electronic correlations are at their prime. In the first part of this talk, we will present our advances in cryo-QTM momentum-resolved imaging.

[1] Inbar, Alon, John Birkbeck, Jiewen Xiao, Takashi Taniguchi, Kenji Watanabe, Binghai Yan, Yuval Oreg, Ady Stern, Erez Berg, and Shahal Ilani. "The Quantum Twisting Microscope." arXiv preprint arXiv:2208.05492 (2022).