Supplementary Figure S1. Raman M bands of few-layer graphene. (a) The M band for the pristine bilayer, trilayer and tetralayer graphene.

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1 Supplementary Figure S1. Raman M bands of few-layer graphene. (a) The M band for the pristine bilayer, trilayer and tetralayer graphene. (b) The M band for the triazine decorated trilayer graphene. (c) The M band for the triazine decorated tetralayer graphene. here is only one asymmetrical peak (P1) centered at around 1740 cm -1 for the Bernel stacked graphene bilayer (AB(2)), trilayer (ABA(3)) and tetralayer (ABA(4)). This peak has been assigned to the M - band and we observe that the peak energy decreases with the number of layer. For the ABC stacked trilayer and tetralayer graphene, the M - peak splits into two peaks: P2 and P3, and the peak intensities decrease. It is noted that our excitation laser is 473nm, different from the 532 nm used in Cong's report. 26 It is known that the M - band energy increases with the decrease of laser wavelength. In our experiments, the positions of P1, P2 and P3 are ~1746cm -1, ~1735cm -1, ~1751cm -1 respectively for the trilayer graphene, and ~1750cm -1, ~1738cm -1, ~1756cm -1 for the tetralayer graphene. The position for the peak at around 1770cm -1 in the M band region is not sensitive to the stacking order and its peak intensity is relatively weak. It has been reported that the peak intensity decreases and position red shifts with the decrease of laser wavelength. 26 In our experiments, we found this peak was around 1765cm -1 for the laser is 473nm, and the peak intensity was very weak.

2 Supplementary Figure S2. The transformation and stability of the stacking order for another trilayer graphene. (a), (b) and (c) are the Raman mapping of 2D FWHM for a pristine trilayer graphene before triazine decoration, after triazine decoration and then after thermal annealing in an argon environment at 500 o C for 5 hours, respectively. The scale bars are 10μm. The areas with bigger FWHM width indicating ABC stacking, and the smaller FWHM width indicating ABA stacking. (d) the optical image of the sample, and the red square corresponds to the Raman mapping area in the panels (a), (b) and (c). (e) and (f) are the M band and 2D band after thermal annealing. The black curves are the Raman peaks of the pristine ABA stacking area, the red curves are the Raman peaks of the converted ABA stacking domains, and the blue curves are the Raman peaks of the original ABC stacking domains.

3 Supplementary Figure S3. Raman M band. The Raman (a) 2D and (b) M bands of the ABC-stacked trilayer graphene after triazine decoration, and after triazine removed by thermal annealing at 500 o C.

4 Supplementary Figure S4. Transformation of stacking order in tetra-layer and hexa-layer graphene. (a) and (b) are the 2D band width mapping before and after triazine decoration respectively, where correspond to the red square in the (c). The dotted lines in the (a) and (b) are the boundaries between the tetra- and hexa-layer. From the (a) and (b), we can find that the area with larger 2D band width decreased after the triazine decoration, and the area with smaller 2D band width increased. (c) The optical micrograph of a graphene flake which contains tetra-layer and hexa-layer. (d) and (e) are the 2D band Raman spectra of the tetra-layer graphene before and after the triazine decoration respectively. (f) and (e) are the 2D band Raman spectra of the hexa-layer graphene before and after the triazine decoration respectively.

5 Supplementary Figure S5. Study of the simulation convergence. The K-point convergence of the energy difference between Bernal and Rhombohedral stacking graphite. Note that the Bernal model contains two unitcells while the Rhombohedral model consists of three unitcells.

6 Supplementary Table S1. The transformation probability (from ABC to ABA stacking order) for 9 samples performed with 150 and 250 o C triazine decoration. The boiling point of 1,3,5-triazine is 114. We have tried two deposition temperatures: 150 and 250. The transformations from ABC to ABA stacking orders were observed at these two deposition temperatures. However, the averaged transformation probability at 150 (~41.3%) is higher than that at 250 (~9.6%). In addition, our experiments have shown that the decorated triazine on the few layer graphene can be evaporated completely removed at 500. Therefore, the decoration process is in competition with the desorption process. Higher temperature (250 o C) likely results in higher triazine desorption efficiency, which may explain its lower conversion probability. Sample Triazine ABC area ABC area Converted Transformation decoration (original) (after area probability Temperature ( ) (μm 2 ) decoration) (μm 2 ) (μm 2 ) # % # % # % # % # % # % # % # % # %

7 SupplementaryTable S2. Comparison of the total energies (ev) of a triazine molecule adsorbed parallel to or perpendicularly on a trilayer graphene sheet for both ABA- and ABC- stacking forms. Shown here are the most stable configurations in both parallel and perpendicular orientation. ABA ABC Perpendicular Parallel

8 Supplementary Table S3. The energy difference (ev) between ABA- and ABC- stacking domains with or without the triazine molecule decoration. The results are computed within the VdW-DF formalism compared with results from LDA calculations. LDA VdW-DF E (ABA-ABC) without triazine E (ABA-ABC) with triazine