Fig. 3: Spatially mapping the band structure of ultra-clean intercalated heterostructures with nanoARPES.

a A schematic depicting the nanoARPES experiment conducted on a Fe_xTaS₂ encapsulated with monolayer hBN. The sample was prepared by selectively applying Fe_xC_yO_z onto the area of 2H–TaS₂ not covered by hBN, followed by vacuum annealing. Normalized ARPES Fermi surface (b) and ARPES band dispersion along the Γ–K direction (c) of a hBN/Fe_xTaS₂ heterostructure at a 4 μm distance from the patterned Fe_xC_yO_z precursor. In (c), the Fermi wavevector (k_F) is marked, denoting where the band forming the hole pocket around Γ intersects the Fermi level (E_F). This band is marked by a white dashed line. Data in (b, c) was obtained at 19 K with hν = 118 eV and linear horizontal (LH) polarization. d k_F along the Γ–K direction extracted from ARPES band-dispersions obtained at different distances from the Fe_xC_yO_z precursor. The k_F values were obtained by fitting the momentum distribution curves (MDCs) at the Fermi level (E_F) to Lorentzians. Error bars represent the standard errors for the center positions of Lorentzian peaks corresponding to the main hole pocket around Γ. The dashed gray line is included as a visual guide. e Schematic of the band forming the hole pocket at Γ as the distance from the precursor increases from spot 1 to 4. f Qualitative d-orbital splitting diagram for the trigonal prismatic Ta center in Fe_xTaS₂. A dashed electron in the \({{{\rm{d}}}}_{{{{\rm{z}}}}^{2}}\) orbital denotes additional electron filling upon Fe intercalation, concomitant with charge transfer to 2H–TaS₂. g Qualitative representation of the density of states of Fe-intercalated 2H–TaS₂.