Hybridization-controlled re-entrant electronic phase switching and moire-confined states in twisted bilayer PtTe2
arXiv:2607.13529
The study uses first‑principles calculations with spin‑orbit coupling to show that twisting a PtTe₂ bilayer causes a non‑monotonic, re‑entrant transition between gapless and gapped electronic states, driven by changes in interlayer hybridization and moiré stacking.
Abstract
Twisting a van der Waals bilayer changes not only the moiré periodicity but also the local stacking and interlayer hybridization. Here, we show, using fully relaxed first-principles calculations including spin--orbit coupling, band unfolding, and Brillouin-zone-integrated densities of states, that bilayer PtTe exhibits a non-monotonic evolution between gapless and gapped electronic regimes. The structure remains gapless, whereas finite direct gaps appear at the sampled intermediate angles. The gap closes at the sampled configuration and reopens at higher angles. The direct gap shows an overall increase with the minimum local interlayer Pt--Pt separation, although the complete distribution of local stacking environments is required to account for deviations from this trend. At , the low-energy states are concentrated predominantly in the AA-like regions of the otherwise gapless moiré cell. Controlled interlayer-separation scans show that increasing the layer spacing removes the near- crossings and opens a gap, consistent with weakened interlayer Te- hybridization. These results identify the redistribution of interlayer hybridization as the microscopic origin of the re-entrant gap evolution in twisted bilayer PtTe.