A quantum ruler for orbital magnetism in moiré quantum matter

Published

October 5, 2023

Author(s)

Marlou Slot, Yulia Maximenko, Paul M. Haney, Sungmin Kim, Daniel Walkup, Evgheni Strelcov, En-Min Shih, Dilek Yildiz, Steven R. Blankenship, Kenji Watanabe, Takashi Taniguchi, Yafis Barlas, Nikolai Zhitenev, Fereshte Ghahari Kermani, Joseph A. Stroscio

Abstract

Topological properties that underlie the rich emergent phases of moiré quantum matter (MQM) result from the eigenstate geometry of the moiré Hamiltonian. The eigenstate geometry involves the Berry curvature and the less known quantum metric. Most studies to date have focused on measurements to identify the Chern topology in MQM, but did not characterize the quantum geometry in detail. For almost a century, magnetic oscillations have been a powerful "quantum ruler" for the analysis of Fermi surfaces. In this report, we use a quantum ruler of Landau levels to probe quantum geometry and topology in twisted double bilayer graphene. We demonstrate significant deviations from Onsager's relation due to anomalously large second-order magnetic susceptibility contributions, relying in part on the quantum metric, and exceeding first-order contributions from the Berry curvature. This breakdown is unique for the large lattice constants typical for MQM.

Citation

Science Magazine

Volume

382

Issue

6666

Pub Type

Journals

Download Paper

https://doi.org/10.1126/science.adf2040

Local Download

Keywords

Moire quantum matter, scanning tunneling microscopy, Landau levels

Citation

Slot, M. , Maximenko, Y. , Haney, P. , Kim, S. , Walkup, D. , Strelcov, E. , Shih, E. , Yildiz, D. , Blankenship, S. , Watanabe, K. , Taniguchi, T. , Barlas, Y. , Zhitenev, N. , Ghahari Kermani, F. and Stroscio, J. (2023), A quantum ruler for orbital magnetism in moiré quantum matter, Science Magazine, [online], https://doi.org/10.1126/science.adf2040, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935604 (Accessed November 3, 2025)