Fig. 2: XLD, resonant photoemission and mass renormalization.

a V L₃ XAS spectra for the 32 nm, 16 and 8 nm thick films (from top to bottom) at 355 K, i.e., the metallic phase. In the reported spectra, the electric field vectors of the incident photon beam were aligned parallel (red spectra) and perpendicular (blue spectra) to the c_r axis, corresponding to impinging angles of α = +45 and −45, respectively (see Fig. 1). The spectra are normalized via the procedure described in ref. ⁴⁷ and vertically shifted for clarity. The photon energy region where the XLD is calculated is highlighted by a black dotted box, chosen in accordance with what was reported in ref. ⁴⁷, to provide the best possible frame of reference for our data. b XLD signal percentage calculated as described in Eq. (1). The broken line acts as a guide. The inset shows a sketch of the \({{\rm{d}}}_{{{||}}}-\pi\) population redistribution as a function of compressive strain and film thickness. c VB spectra at V L₃ edge resonance for the metallic phase of the VO₂/TiO₂(101) films acquired with light polarization directed parallel and perpendicular to the c_r axis. The spectra are normalized with respect to the incident photon flux and vertically shifted for clarity. d Screening length linear dichroism (in red, left axis) and effective mass linear dichroism (in black, right axis) calculated via Eqs. (4) and (5), respectively. The belts represent the uncertainty range for the points. Between the experimental points, the uncertainty value is interpolated via a polynomial function.