We investigated the Dirac-cone state and its modulation when an ultrathin film of topological insulator Bi2Se3 was epitaxially grown on a van der Waals ferromagnet Cr2Si2Te6 (CST) by angle-resolved photoemission spectroscopy. We observed a gapless Dirac-cone surface state in six quintuple-layer (6QL) Bi2Se3 on CST, whereas the Dirac cone exhibits a gap of 0.37 eV in its 2QL counterpart. Intriguingly, this gap is much larger than those for Bi2Se3 films on Si(111). We also revealed no discernible change in the gap magnitude across the ferromagnetic transition of CST, suggesting the very small characteristic length and energy scale of the magnetic proximity effect. The present results suggest a crucial role of interfacial coupling for modulating Dirac electrons in topological-insulator hybrids.
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy (miscellaneous)