上海科技大学知识管理系统

Two-dimensional electron systems in both magnetic fields and periodic potentials are described by the Hofstadter butterfly, a fundamental problem of solid-state physics. While moire systems provide a powerful method to realize this type of spectrum, previous experiments have been limited to fractional flux quanta regime, due to the difficulty of building similar to 50 nm periodic modulations. Here, we demonstrate a super-moire strategy to overcome this challenge. By aligning monolayer graphene (G) with 1.0 degrees twisted hexagonal boron nitride (t-hBN), a 63.2 nm bichromatic G/t-hBN super-moire is constructed, made possible by exploiting the electrostatic nature of t-hBN potential. Under magnetic field B, magnetic Bloch states at phi/phi(0) = 1 - 9 are achieved and observed as integer Brown-Zak oscillations, expanding the flux quanta from fractions to integers. Theoretical analysis reproduces these experimental findings. This work opens promising avenues to study unexplored Hofstadter butterfly, explore emergent topological order at integer flux quanta and engineer long-wavelength periodic modulations.