Supersolid skin thermal stability.^[57] Temperature dependence of (a) the full-frequency Raman spectra and (b) the frequency shift of the bulk, skin, and H–O dangling bond components. The H–O dangling bond undergoes thermal expansion (redshift) at T > 300 K. Both the bulk and the skin components undergo thermal contraction, at different slopes. At T > 340 K, the skin component turns to be thermal elongation, showing the O—O repulsive weakening.