The Quantum Twisting Microscope: Image quantum matter in momentum space
by
Tsung-Dao Lee Institute/N4F-N400 - meeting room
Tsung-Dao Lee Institute
Host: Prof. Haibiao Zhou
Venue: TDLI Meeting Room N400
Tencent Meeting link: https://meeting.tencent.com/dm/ACv1c71p6a1Y Meeting ID: 972189086, no password
Abstract:
Measuring the energy–momentum dispersion of quantum materials provides key insights into their strongly correlated electronic phenomena. We have recently developed a new type of scanning probe microscope—the Quantum Twisting Microscope (QTM)—which allows direct momentum-space imaging of electrons, analogous to how a scanning tunneling microscope (STM) probes electronic states 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 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. In the first part of my talk, I will introduce how the QTM can directly image phonon modes in twisted bilayer graphene, allowing us to resolve the momentum- and mode-dependent electron–phonon coupling. In the second part, I will present the first image of the strongly interacting energy bands of magic-angle twisted bilayer graphene (MATBG), offering a direct window into the underlying correlated electronic structure.
Biography:
Jiewen Xiao received his Bachelor degree from Beihang University in 2020. He then pursued his Master’s and PhD studies at the Weizmann Institute of Science in Israel, where he worked under the supervision of Professors Shahal Ilani and Binghai Yan during his Master’s, and Shahal Ilani and Erez Berg during his PhD. His doctoral research centered on the invention and development of a novel scanning microscope—the quantum twisting microscope (QTM)—capable of performing local interference experiments and probing electrons in momentum space. This groundbreaking work involved utilizing van der Waals tips to create pristine two-dimensional junctions, enabling the study of coherent electron tunneling and strongly interacting energy bands in graphene moiré systems. Jiewen has made significant contributions to the fields of quantum materials and instrumentation, with his research findings published in prestigious journals such as Nature (2 already published, 1 to be submitted), Nature Materials (1) and Physical Review B as a leading author.
