studied by high-resolution ARPES*

We have epitaxially fabricated Bi₂Se₃ thin films on van der Waals ferromagnet, Cr₂Si₂Te₆ (CST), and investigated their electronic structure by high-resolution angle-resolved photoemission spectroscopy (ARPES) [1]. We observed a large energy gap at the Dirac point in 2 quintuple-layer (QL) Bi₂Se₃ on CST in contrast to the gapless Dirac-cone state in 6 QL Bi₂Se₃ on CST. Compared to 2 QL Bi₂Se₃ on Si substrate, we found that the Dirac point of 2 QL Bi₂Se₃ on CST is located at lower binding energy with enhanced gap magnitude. In this talk, we will show temperature dependence of band structure across T_C of CST, and discuss the origin of modulation of Dirac electronic states in Bi₂Se₃/CST heterostructure in terms of the lattice strain effect, interfacial coupling, and magnetic proximity effect.
[1] T. Kato et al., Phys. Rev. Mater. 4, 084202 (2020).