Quantum twisting microscope reveals electron interactions in graphene at room temperature

Researchers from Ludwig-Maximilians-Universität München (LMU Munich), Princeton University, Peking University, University of Florida, Basque Foundation for Science, Technical University of Munich, and Japan’s National Institute of Material Sciences have built an advanced Quantum Twisting Microscope (QTM) that can observe, with unprecedented precision, the interactions between electrons in graphene – even at room temperature. The study, led by Professor Dmitri Efetov from LMU’s Faculty of Physics and co-coordinator of the Munich Center for Quantum Science and Technology (MCQST), marks a major leap forward in the direct measurement of quantum many-body effects in two-dimensional (2D) materials.

uantum Twisting Microscope in Munich. Inage credit: MCQST

At its core, the QTM enables energy- and momentum-resolved tunneling spectroscopy between two atomically thin layers with a controllable twist angle. By integrating a hexagonal boron nitride (hBN) layer as a tunneling dielectric, the team significantly improved both the energy resolution and the operational range of twist angles. This enhancement allowed researchers to access previously hidden dispersion features in tunneling spectra between two monolayer graphene sheets. The measurements revealed a logarithmic correction to graphene’s linear Dirac spectrum, a hallmark of electron-electron interactions long predicted but never before observed under ambient conditions. The extracted fine-structure constant, α ≈ 0.32 ± 0.01, quantifies the interaction strength and aligns closely with theoretical expectations.

uantum Twisting Microscope in Munich. Inage credit: MCQSTAt its core, the QTM enables energy- and momentum-resolved tunneling spectroscopy between two atomically thin layers with a controllable twist angle. By integrating a hexagonal boron nitride (hBN) layer as a tunneling dielectric, the team significantly improved both the energy resolution and the operational range of twist angles. This enhancement allowed researchers to access previously hidden dispersion features in tunneling spectra between two monolayer graphene sheets. The measurements revealed a logarithmic correction to graphene’s linear Dirac spectrum, a hallmark of electron-electron interactions long predicted but never before observed under ambient conditions. The extracted fine-structure constant, α ≈ 0.32 ± 0.01, quantifies the interaction strength and aligns closely with theoretical expectations.

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