Fig. 2: Heat treatment-induced migration of Te-SAVs in PtTe₂.

a Large-scale STM image of thin PtTe₂ sheets taken at V_S = −2.0 V and I = 30 pA. b Close-up STM image showing three individual Te-SAVs on the surface of thin PtTe₂ sheets with the corresponding structural model superimposed. The yellow and blue atoms represent Te and Pt atoms, respectively. Te atoms at the bottom of PtTe₂ structural model are omitted. c Statistic distance of neighboring Te-SAVs in thin PtTe₂ sheets before heat treatment. d Large-scale STM image of thin PtTe₂ sheets after heat treatment. e Close-up STM image showing the formation of ordered trigonal Te-SAV clusters on the surface of thin PtTe₂ sheets after heat treatment with the corresponding structural model superimposed. Te atoms at the bottom of PtTe₂ structural model are omitted. f Statistic distance of neighboring Te-SAVs in thin PtTe₂ sheets after heat treatment. The error bars in c and f represent standard deviation of different technical replicates. g Stacking plots of the in situ Pt L₃-edge XANES spectra of PtTe₂ NSs collected from room temperature to 600 °C in He gas (left), and the corresponding 2D contour plots of the in situ Pt L₃-edge XANES spectra as shown in g (right), revealing the positive shift of the white line. h Normalized Pt L₃-edge XANES spectra for PtTe₂ NSs, PtTe₂-600 NSs, and Pt foil. i Fourier-transformed k³-weighted EXAFS spectra for PtTe₂ NSs, PtTe₂-600 NSs, and Pt foil.