Nanosecond Phase‐Transition Dynamics in Elemental Tellurium

Abstract

AbstractElemental tellurium, a prototypical one‐dimensional van der Waals material, has recently been found to crystallize quickly from the liquid on a nanosecond timescale, yet the inherent mechanism is not clear. Here, by combining in situ high‐energy synchrotron radiation X‐ray diffraction with ab initio molecular‐dynamics simulation, it is found that trigonal crystalline Te completely melts into the liquid phase at 450 °C, and recrystallizes into the trigonal phase for temperatures lower than 380 °C without the formation of any other phase. This directly confirms the recent proposal of a crystal‐liquid‐crystal phase transition in this material underlying the observed electrical‐switching process. Atomic‐scale, melt‐quench computer simulations show that liquid Te is capable of crystallizing within a time of 25 ps in the vicinity of templating crystallization interfaces. This ultrafast crystallization ability of Te can be understood as being due to delayed Peierls distortions during a quench and therefore a high atomic mobility over a wide range of temperature. This finding opens the way to develop a crystal‐liquid‐crystal, phase‐transition‐based selector switch with an ultrafast switching speed.