Geometrically Induced Emergent Band in Electronic Structures of van der Waals Moiré Bilayer: PtSe₂/PtTe₂

Yin-Song Liao^1*, Cheng-Maw Cheng², Meng-Kai Lin³, Jyh-Pin Chou¹

¹Graduate School of Advanced Technology, National Taiwan University, Taipei, Taiwan
²National Synchrotron Radiation Research Center, Hsinchu, Taiwan
³Department of Physics, National Central University, Taoyuan, Taiwan

* Presenter:Yin-Song Liao, email:lyson0921@gapp.nthu.edu.tw

Van der Waals heterostructures enabled by stacking of few atomic layers hold attraction for condensed matter physics community. Though the weak interlayer bonding through van der Waals force, the interfacial effects such as electronic hybridization and moiré modulation could lead to the emergent phenomena such as the superconductivity and novel electronic correlations. Herein, we comprehensively investigated the PtSe2/PtTe2 heterostructure using first-principles calculation with density functional theory (DFT) and angle-resolved photoemission spectroscopy (ARPES). Presenting an integrated theoretical-experimental study to elucidate both the geometric and electronic structure of PtSe₂/PtTe₂ heterostructure, highlighting the critical role of geometric buckling and spin-orbit coupling (SOC) effects in modulating the electronic structure. We demonstrate the interlayer coupling in PtSe₂/PtTe₂ can lead to the emergence of exotic band features such as the flat bands and giant valence bands splitting induced both by inversion symmetry breaking and SOC. The local density of states (LDOS) further reveals a transition to metallic behavior at MM site while remains semiconductor characteristics at MX and XX sites with the bandgap of 0.40 and 0.25 eV. These findings establish the prototypical platform for the investigation of electronic phenomena of two-dimensional van der Waals materials.

Keywords: van der Waals heterostructures, 2D materials, electronic structure