Ultrathin topological insulator membranes are building blocks of exotic quantum matter. However, traditional epitaxy of these materials does not facilitate stacking in arbitrary orders, while mechanical exfoliation from bulk crystals is also challenging due to the non-negligible interlayer coupling therein. Here we liberate millimeter-scale films of topological insulator Bi2Se3, grown by molecular beam epitaxy, down to 3 quintuple layers. We characterize the preservation of the topological surface states and quantum well states in transferred Bi2Se3 films using angle-resolved photoemission spectroscopy. Leveraging the photon-energy-dependent surface sensitivity, the photoemission spectra taken with 6 eV and 21.2 eV photons reveal a transfer-induced migration of the topological surface states from the top to the inner layers. By establishing clear electronic structures of the transferred films and unveiling the wavefunction relocation of the topological surface states, our work paves the physics foundation crucial for the future fabrication of artificially stacked topological materials with single-layer precision.
@article{arxiv.2405.13228,
title = {Preservation of Topological Surface States in Millimeter-Scale Transferred Membranes},
author = {Chi Ian Jess Ip and Qiang Gao and Khanhy Du Nguyen and Chenhui Yan and Gangbin Yan and Eli Hoenig and Thomas S. Marchese and Minghao Zhang and Woojoo Lee and Hossein Rokni and Ying Shirley Meng and Chong Liu and Shuolong Yang},
journal= {arXiv preprint arXiv:2405.13228},
year = {2024}
}