Melting Temperature Under Pressure in ‘Hard’ and Soft Matter

This report focuses on cognitive gaps of the pressure dependence of melting temperature, presenting: (i) a coherent discussion on Tm(P) behavior for both ‘Hard Matter’ (‘standard’ solid state) and Soft Matter systems, to reveal the importance of the strength of intermolecular interactions; (ii) a model picture linking systems with dTm/dP>0, dTm/dP<0, and the TmP curve maximum, which also shows the relevance of the negative-pressure domain; and (iii) the ultimate validation test of the recent ‘universal’ parabolic scaling of Pm(T) against empirical data. The evidence for ‘Hard Matter’ focuses on systems relevant to the semiconductor industry: silicon, germanium, and gallium nitride. For Soft Matter, these include unique polymeric systems and liquid-crystalline pentylcyanobiphenyl (5CB). For the latter, symmetry-selected melting/freezing takes place. Finally, the report presents the specific case of graphite and diamond. The report also presents an innovative solution for melting-temperature and pressure detection.