Heat and pressure are agents commonly applied to induce the melting of metals. For example, temperatures as high as 1064° C (1948° F) are required to melt gold.

Another trigger has been demonstrated by an international team of researchers. Intense electric fields were Atoms of a gold cone exposed to a strong electric field. Note the field around the tip of the cone that excites the gold atoms, causing them to break almost all interconnections as the surface layers begin to melt. Source: Alexander Ericsonshown to induce reversible switching between crystalline and disordered phases of gold surfaces. No excessive heat regime was required, as the process occurred at room temperature.

As observed under an electron microscope, gold atoms lost their ordered structure as the metal morphed from a solid to a molten structure. The process is reversible, as switching off the electric field results in re-solidification of gold. Simulations attribute the physical change to the formation of surface defects under high electric fields. The surface melting is also theorized to result from low-dimensional phase transition mechanisms.

What are the practical implications of melting gold at room temperature? The process provides opportunities for the development of nanophotonic and nanophotocatalytic devices, such as field-effect transistors and sensors. The finding could also advance research in materials characterization and new dynamically controlled low-dimensional phases of matter.

Scientists from Chalmers University of Technology (Sweden), University of Jyväskylä (Finland), University of Gothenburg (Sweden) and Stanford University contributed to this research, which is published in Physical Review Materials.